cmake support

[fr0stbyte]

@srdja I am curious if you would entertain the idea of using cmake instead of make/autotools.
The advantage would be a little bit more modern build system, integration with testing frameworks, possibly building .rpm/.deb easier.
Speaking of testing frameworks, was wondering why not use something like CppUTest instead of rolling your own.
I understand the portability aspect of autotools, but cmake is readily available on many platforms.

[srdja]

I agree that cmake is more usable (less terrible? :-) than autotools, but at the time when I started the project I wasn't all that familiar with cmake so I just went with what I knew, which was autotools. Same thing happened with the testing framework. It was much easier to quickly hack together my own than to look for some external frameworks. Now, in retrospect, these may not have been the ideal choices, but the whole thing worked just fine and there was no real reason to change it.

That being said, I definitely like the idea of porting the project to cmake.

[srdja]

Implemented in #70