Remove unused class members.

GMSHInterface: _include_stations_as_constraints
FileIO/Legacy/MeshIO.h: _edge_length[]
Braces around array init lists. Whitespaces.
Correct doxygen parameters.
Extra semicolon.
[ML] Replace deprecated throw() with noexcept.
Find Boost also in C:/libs/boost.
Merge pull request #441 from endJunction/FixingWarnings

Fixing warnings
Enable caching of apt-get install on Travis.
Merge pull request #288 from bilke/travis-apt-cache

Enable caching of apt-get install on Travis.
[ML] Remove noexcept(false).

Stating noexcept(false) is equivalent to no exception specifier. See par. 15.4 Exception specification.

This also fixes compilation on windows #441.