added: rules for ignoring precompiled headers for C/C++

What's precompiled headers: http://en.wikipedia.org/wiki/Precompiled_header

`*.gch` for GCC, see https://gcc.gnu.org/onlinedocs/gcc/Precompiled-Headers.html
`*.pch` for MSVC, see http://msdn.microsoft.com/en-us/library/szfdksca.aspx