- added MSVC cmake definitions to disable warnings
- general.c is rewritten so it is ansi-c compatible and compiles ok on microsoft windows
- some MSVC reported warning fixes
This reorganizes a few of the examples so that the main function
comes first with the argument parsing extracted into a helper
that can come at the end of the file (so the example focuses more
on the use of libgit2 instead of command line support). This also
creates a shared examples/common.[ch] so that useful helper funcs
can be shared across examples instead of repeated.
