Added support for C projects.
- New parameter for Project constructor 'outname', which specifies the
  output name of the project (excl. the directory name).
- Makefiles now default to the name "makefile"
- Makefiles will generate the output directories as needed.
- Fixed bug where PCH for "c-header" used C++ compiler instead of C.
Added compiler flag testing feature.
- Precompiled header projects can be included directly using a parameter.
- Linker-specific flags can now be specified.
- "-std" flags are stripped from linker flags automatically.