Add CMake support

[Alexander Zaitsev]

Hello,
as i see in your library there are strange build scripts.
Can you use instead this CMakeLists.txt? You will get one build script for windows, linux platforms.

[L. Le Meur]

Dear @zamazan4ik, the Readium SDK is a community driven effort, meaning that "You" are part of the "We". The windows support has always been weak, because the community didn't focus on it (same for Linux). Volunteers are welcome to help on this.