Some changes to build on FreeBSD, custom prefix...

Hello, your project is awesome :D

I made some changes and I'd like to know what do you think.

- Now I can build it on FreeBSD
- Now I can install AND run in a custom prefix (-DCMAKE_INSTALL_PREFIX=/tmp/craft)
- The embedded libglfw are not installed anymore, once it is statically linked with the main binary
- I merged the sqlite 3.8.2, the version you are using doesn't build on FreeBSD.