Generate pseudo-random test data on the fly
Added the header files from include/ to file list

Some IDEs, for example Qt Creator, are able to open CMakeLists.txt as a
project, but need all relevant files to be listed in the CMakeLists.txt
file.
add a build target for test_vertex_enum
Put the library under a namespace
Simplified vertex enum code and added to zonotope_c

Simplified the vertex enumeration code and added a C-interface to it.
Also updated CMakeLists.txt and tests/ to account for the changes.
Added vertex enum (long) to the python interface