Addition of a build system generator

[elfring]

I suggest to reuse a higher level build system than your current small make file so that powerful checks for software features will become easier.

• CMake
• Autotools

[tdaede]

Pull request #10 adds autotools support. Would you be up for reviewing it?

[awakecoding]

@elfring @tdaede my branch uses cmake, but it is heavily modified from the current master. However, the build system can be used as an example. https://github.com/awakecoding/thor/tree/torn