Revert "Conditionally install man page into system or virtualenv.  For #39."

This reverts commit 720ac2f93e6dfb1c77520dc5f7aeab4f031dfd75.

Conflicts:
	setup.py
Install man page to ${PREFIX}, not /usr (issue #39)
Merge pull request #42 from hartwork/issue-39

Generic approach to issue 39