[Documentation] Rename COPYING to LICENSE.md

This will help GitLab show license information and format it correctly.

COPYING

-Copyright holders:
-
-2009--2014    Peter Bastian
-2009--2014    Markus Blatt
-2013          Andreas Buhr
-2014          Ansgar Burchardt
-2011          Martin Drohmann
-2009--2014    Christian Engwer
-2009--2013    Jorrit Fahlke
-2012--2014    Christoph Grüninger
-2009--2012    Felix Heimann
-2014          René Heß
-2013--2014    Pavel Hron
-2010--2011    Ole Klein
-2009--2010    Sven Marnach
-2010--2014    Steffen Müthing
-2010--2013    Rebecca Neumann
-2011--2013    Adrian Ngo
-2013          Andreas Nüßing
-2014          Marian Piatkowski
-2012--2013    Jurgis Pods
-2011          Hanna Remmel
-2012          Human Rezaijafari
-2014          Oliver Sander
-2012          Nicolas Schwenck
-2013          Bård Skaflestad
-2012          Christian Waluga
-2013          Sebastian Westerheide
-2012          Matthias Wohlmuth
-
-
-
-The PDELab library, headers and test programs are copyrighted free software. You
-can use, modify and/or redistribute it under the terms of either one of the two
-following licenses:
-
-* The GNU Lesser General Public License as published by the Free Software
-  Foundation, either Version 3 of the license or (at your option) any later
-  version. You can find a copy of the GNU Lesser General Public License, Version
-  3, in the files GPL-3 and LGPL-3 or at <http://www.gnu.org/licenses/lgpl-3.0>.
-
-* Version 2 of the GNU General Public License as published by the Free Software
-  Foundation, with the following special exception for linking and compiling
-  against the PDELab library, the so-called "runtime exception":
-
-    As a special exception, you may use the PDELab source files as part of a
-    software library or application without restriction.  Specifically, if other
-    files instantiate templates or use macros or inline functions from one or
-    more of the PDELab source files, or you compile one or more of the PDELab
-    source files and link them with other files to produce an executable, this
-    does not by itself cause the resulting executable to be covered by the GNU
-    General Public License.  This exception does not however invalidate any
-    other reasons why the executable file might be covered by the GNU General
-    Public License.
-
-  This license is intended to be similar to the GNU Lesser General Public
-  License, Version 2, which by itself isn't suitable for a template library. You
-  can find a copy of the GNU General Public License, Version 2, in the file
-  GPL-2 or at <http://www.gnu.org/licenses/gpl-2.0>.

COPYING

+LICENSE.md
\ No newline at end of file

LICENSE.md

+Copyright holders:
+
+2009--2014    Peter Bastian
+2009--2014    Markus Blatt
+2013          Andreas Buhr
+2014          Ansgar Burchardt
+2011          Martin Drohmann
+2009--2014    Christian Engwer
+2009--2013    Jorrit Fahlke
+2012--2014    Christoph Grüninger
+2009--2012    Felix Heimann
+2014          René Heß
+2013--2014    Pavel Hron
+2010--2011    Ole Klein
+2009--2010    Sven Marnach
+2010--2014    Steffen Müthing
+2010--2013    Rebecca Neumann
+2011--2013    Adrian Ngo
+2013          Andreas Nüßing
+2014          Marian Piatkowski
+2012--2013    Jurgis Pods
+2011          Hanna Remmel
+2012          Human Rezaijafari
+2014          Oliver Sander
+2012          Nicolas Schwenck
+2013          Bård Skaflestad
+2012          Christian Waluga
+2013          Sebastian Westerheide
+2012          Matthias Wohlmuth
+
+
+
+The PDELab library, headers and test programs are copyrighted free software. You
+can use, modify and/or redistribute it under the terms of either one of the two
+following licenses:
+
+* The GNU Lesser General Public License as published by the Free Software
+  Foundation, either Version 3 of the license or (at your option) any later
+  version. You can find a copy of the GNU Lesser General Public License, Version
+  3, in the files GPL-3 and LGPL-3 or at <http://www.gnu.org/licenses/lgpl-3.0>.
+
+* Version 2 of the GNU General Public License as published by the Free Software
+  Foundation, with the following special exception for linking and compiling
+  against the PDELab library, the so-called "runtime exception":
+
+    As a special exception, you may use the PDELab source files as part of a
+    software library or application without restriction.  Specifically, if other
+    files instantiate templates or use macros or inline functions from one or
+    more of the PDELab source files, or you compile one or more of the PDELab
+    source files and link them with other files to produce an executable, this
+    does not by itself cause the resulting executable to be covered by the GNU
+    General Public License.  This exception does not however invalidate any
+    other reasons why the executable file might be covered by the GNU General
+    Public License.
+
+  This license is intended to be similar to the GNU Lesser General Public
+  License, Version 2, which by itself isn't suitable for a template library. You
+  can find a copy of the GNU General Public License, Version 2, in the file
+  GPL-2 or at <http://www.gnu.org/licenses/gpl-2.0>.