Specify lower-bound Sphinx version

Not sure 1.2 is necessary, but hieroglyph does not run with Sphinx 1.0
Change Sphinx dependency to 1.1

According to @nyergler 1.1 should be sufficient, I hadn't thought to
check travis or tox's conf files for the information.
Merge pull request #73 from xmo-odoo/patch-1

Specify lower-bound Sphinx version