Cygwin port

As a big fan of your rtags project, I had a working setup on Linux but my windows machine running cygwin wasn't able to build it for several reasons.  I ported rct to run on Cygwin with the following [major] changes:

1. EventLoop rewritten based on libevent (Cygwin doesn't have kqueue or epoll - and libevent internally chooses the 'best' backend anyways)

2. rct didn't have a file system monitoring backend compatible with cygwin - so I added another filesystem monitor based on FAM.  It's only chosen if the HAVE_FAM is set.

3. CMake files were edited/hacked to work with my cygwin setup.  There were some dependency issues and cflag issues

Though there are lots of changes to the guts of EventLoop, I kept your interface the same; and though it introduces another external dependency (libevent -> https://github.com/libevent ), I believe you'll find the code readability is improved.

I confess that I don't have a Mac machine to test with, but I have verified basic operation on Linux machines with gcc 4.7.x, 4.8.1, and Cygwin 4.7.2, and 4.8.0.

Feel free to take the parts (if any) that are useful and fire back with flames/comments/etc.  Hope it's useful!