Latest suggested changes to the tech docs

These are the same changes required to complete / fix the technical documentation that I've submitted to @peterkwells for approval this morning at [https://docs.google.com/a/openaddress.es/document/d/1dDvh_Zrs7jlXvS_l21CnGQXU4MsU_8wCbmAOTvufXmM/edit](https://docs.google.com/a/openaddress.es/document/d/1dDvh_Zrs7jlXvS_l21CnGQXU4MsU_8wCbmAOTvufXmM/edit). Please check with Peter before pulling.