ENH: do allow True and False for EnsureBool

This is how they look in Python so it is only native to state them as
such in environment variables and crash stating that True is not bool
is confusing to say the least
Merge pull request #203 from yarikoptic/master

ENH: do allow "True" and "False" for EnsureBool
BF: Adjust manpage generation to changes in cmdline interface
Merge branch 'master' of github.com:PyMVPA/PyMVPA

* 'master' of github.com:PyMVPA/PyMVPA:
  ENH: do allow True and False for EnsureBool
RM: Remove cmdline examples that are now duplicates
DOC: Polish examples.
DOC: Basic set of documented cmdline example scripts
DOC: Refresh installation instructions.
DOC: Update and fix installation instructions.
DOC: A bit of front-page tweaking