Revert "Added StatusMessage convenience funcs. Closes #74."

This reverts commit c1cf13423e7b0d6d2974aaf4fbe9e023074f9339.

Conflicts:
	libtaxii/messages_11.py
Revert "Updated tests to account for StatusMessage convenience"

This reverts commit 4d4b3e90d2c240a68083e7eba7154a332c18f47c.
Revert "Added documentation"

This reverts commit 4f4fac5fd572d62662159e1a004d7dac6bfee436.

Conflicts:
	libtaxii/messages_11.py