updated headers to comply to naming convention for header-ifdefs

common/bigunsignedint.hh

common/capabilities.hh

common/fixedarray.hh

common/function.hh

common/mapping.hh

common/operator.hh

common/precision.hh

common/simplevector.hh

common/smartpointer.hh

common/test/iteratorfacadetest.hh

common/test/iteratortest.hh

common/typetraits.hh

common/vectorspace.hh

disc/functions/functions.hh

disc/functions/p0function.hh

disc/functions/p1function.hh

disc/groundwater/groundwater.hh

disc/groundwater/p1groundwater.hh

disc/operators/p1operator.hh

disc/shapefunctions/lagrange/cubeshapefunctions.hh