Differentiate types of definitions in cscope

so not everything shows up as a function anymore (class show up as classes etc)
Only put relevant files in cscope trailer
Tag function endings in cscope export

These are necessary for vim's cscope integration to work.
export modules as classes to cscope, since it has no other equivalent
Merge pull request #1 from eapache/cscope_export

Cscope export