Options help text improved

Change-Id: I409b25a0767df053a3e80dcef467e99ac30417e4
PY2RPM helper

* PY2RPM helper added.
* All py2rpm related functionality moved from yum.py
  and is used via py2rpm helper.

Implements: blueprint py2rpm-helper
Change-Id: If58541bce2ce2b93b04fb2abedd4615c5bda0669
Merge "Options help text improved"
Merge "PY2RPM helper"