Revise pinned requirements for sayit & co

* Pin sayit to 'pombola' branch, as that is a branch specifically
designed to always be deployable for pombola.

* Pin za-hansard to 'master', as za-hansard only integrates with
pombola, so master should always be deployable.

* Add -e flag for above, to make sure they are re-installed on change.

* NB: Retain specific commits for popit-django and popit-resolver