[!126] Make tolerances in checkGeometry depending on ctype

Merge branch 'issue/check_geometry_tolerances' into 'master'

ref:core/dune-geometry

### Summary

Replaces fixed tolerances 1.e-8 with ctype dependent tolerance

### Details

Tests with geometries using float as ctype may fail to reach the desired fixed
tolerance 1.e-8. This is corrected by using the
tolerance=sqrt(numeric_limits<ctype>::epsilon()) value. This value gives
approximately

-   `tolerance<double> = 1.5e-8` and
-   `tolerance<float> = 3.5e-4`

and thus previous test runs with ctype=double should also pass the test with
this change.

See merge request [core/dune-geometry!126]

  [core/dune-geometry!126]: gitlab.dune-project.org/core/dune-geometry/merge_requests/126

dune/geometry/test/checkgeometry.hh

@@ -154,7 +154,7 @@ namespace Dune
       const typename TestGeometry::LocalCoordinate &x = ip.position();
 
       // Test whether the methods 'local' and 'global' are inverse to each other
-      if ( (x - geometry.local( geometry.global( x ) )).two_norm() > 1e-8 ) {
+      if ( (x - geometry.local( geometry.global( x ) )).two_norm() > tolerance ) {
         std::cerr << "Error: global and local are not inverse to each other." << std::endl;
         pass = false;
       }
@@ -203,7 +203,7 @@ namespace Dune
       bool isId = true;
       for( int j = 0; j < mydim; ++j )
         for( int k = 0; k < mydim; ++k )
-          isId &= (std::abs( id[ j ][ k ] - (j == k ? 1 : 0) ) < 1e-8);
+          isId &= (std::abs( id[ j ][ k ] - (j == k ? 1 : 0) ) < tolerance);
       if( !isId)
       {
         std::cerr << "Error: jacobianTransposed and jacobianInverseTransposed are not inverse to each other." << std::endl;
@@ -226,12 +226,12 @@ namespace Dune
           for( int k = 0; k < coorddim; ++k )
             jtj[ i ][ j ] += jtAsFieldMatrix[ i ][ k ] * jtAsFieldMatrix[ j ][ k ];
 
-      if( std::abs( std::sqrt( jtj.determinant() ) - geometry.integrationElement( x ) ) > 1e-8 ) {
+      if( std::abs( std::sqrt( jtj.determinant() ) - geometry.integrationElement( x ) ) > tolerance ) {
         std::cerr << "Error: integrationElement is not consistent with jacobianTransposed." << std::endl;
         pass = false;
       }
       if (geometry.affine())
-        if( std::abs( geometry.volume() - refElement.volume()*geometry.integrationElement( x ) ) > 1e-8 ) {
+        if( std::abs( geometry.volume() - refElement.volume()*geometry.integrationElement( x ) ) > tolerance ) {
           std::cerr << "Error: volume is not consistent with jacobianTransposed." << std::endl;
           pass = false;
         }