Fix #403 Add sysinfo commands

Now prints out the version of Freeseer as well as versions of various
Freeseer dependencies when the parameter '--version' is passed.

Example: freeseer --version
Freeseer version 3.0.9999 (linux2)
Python version 2.7.6
PyGst version 0.10
Yapsy version 1.10.1

Change-Id: Idf0644d7478397fbae94c48943ea9b0cd26d8949
Signed-off-by: Thanh Ha <thanh.ha@alumni.carleton.ca>