Reindent some of the documentation and code.
Restore backward compatible by converting 'if (' to 'if(' in expressions we pass down to muparser.
fix several doxygen warnings
Fix instantiation issue with FlatManifold properly

This commit reverts the quick fix in commit 982b0683.

This commit closes #56

The issue why we encountered unresolved references to
dealii::FlatManifold<3, 2>::FlatManifold(dealii::Point<2, double>, double)
etc. was due to boilerplate instantiations of Triangulation::get_manifold
for cases with spacedim < dim (in order to make TriaAccessor happy).

This commit fixes the issue by using a nullptr-dereference in order to
return an invalid object - the specific code throws an error message before
that and should actually not be reachable at all.
Also update the parsing of all other builtin functions.
Merge pull request #66 from tjhei/fix_doxygen_warnings

fix several doxygen warnings
Merge pull request #63 from tamiko/fix_manifold_instantiations

This commit reverts the quick fix in commit 982b0683.

The issue why we encountered unresolved references to
dealii::FlatManifold::FlatManifold(dealii::Point, double)
etc. was due to boilerplate instantiations of Triangulation::get_manifold
for cases with spacedim < dim (in order to make TriaAccessor happy).

This commit fixes the issue by using a nullptr-dereference in order to
return an invalid object - the specific code throws an error message before
that and should actually not be reachable at all.
Added FunctionManifoldChart
Added two test files for FunctionManifoldChart
Added changelog
Fix a typo.

Then continue to add some more to the documentation in the form of an example.
Merge pull request #65 from bangerth/fix-muparser-if

Change the parsing of functions in muparser.
muparser requires that there be no space between the name of a function and its argument
list. This is incompatible to the behavior we had with fparser that allowed for spaces
in this position. To allow for backward compatible behavior, this patch changes the
parsing in such a way that it eats spaces after the function name for all built-in
and deal.II-defined functions before passing the expression to muparser.

This addresses bug #218 at https://code.google.com/p/dealii/issues/detail?id=218 .
Added relative tolerance, and better comment for owns_pointers.
Refactored FunctionManifold.
Refactored ManifoldChart to ChartManifold.
Made FlatManifold tolerance relative.
Provide some more documentation.
Merge pull request #69 from bangerth/doc-fixes-6

Fix a typo in the documentation of MappingChart.
Merge pull request #67 from luca-heltai/function_manifold_chart

Function manifold chart