Small implementation improvements in MCF algorithms (#180)

- Handle max() as infinite value (not only infinity()).
- Better GEQ handling in CapacityScaling.
- Skip the unnecessary saturating operations in the first phase in
CapacityScaling.
- Use vector<char> instead of vector<bool> and vector<int> if it is
possible and it proved to be usually faster.

INCLUDE(FindPackageHandleStandardArgs)

FIND_PROGRAM(GHOSTSCRIPT_EXECUTABLE

  NAMES gs gswin32c

  PATHS "$ENV{ProgramFiles}/gs"

  PATH_SUFFIXES gs8.61/bin gs8.62/bin gs8.63/bin gs8.64/bin gs8.65/bin

  DOC "Ghostscript: PostScript and PDF language interpreter and previewer."

)

FIND_PACKAGE_HANDLE_STANDARD_ARGS(Ghostscript DEFAULT_MSG GHOSTSCRIPT_EXECUTABLE)