Refactor

Details:
- move main.cc to sim directory
- add flag for short displaying (power only)
Refactor N-dimensional point

Details:
- change class name NDimPoint -> Point
- change namespace tgm -> ndim
Move to *.hh/*.cc extensions
Add Vector

Details:
- add (at this moment pointless) move constructor to ndim::Point
- create ndim::Vector (N-dimensional vector -- a very early implementation)
- add graph generating scripts (bash + gnuplot)
- update .gitignores, etc...
Update itpp qam sim && minor updates

Details:
- add gflags interface to main.itpp.qam.cc
- add python graph drawing scripts