Move shared configuration settings to common configuration file

- Common configuration moved to common/conf.py
- Move themes to common/
Add central Makefile to build OMERO & Formats documentations at once

Also allows Travis script command to remain unchanged
Move additional FSlite file to the new structure
Merge pull request #324 from sbesson/rebased/develop/doc_reorganization

Doc reorganization (rebased onto develop)
Fix OME Model documentation title and plone menu layout
Fix HTML landing page title
Merge pull request #328 from sbesson/rebased/develop/formats_title

Fix OME Model documentation title and plone menu layout (rebased onto develop)
Fixing links to new formats docs
Fixing roi link
Really fixing the roi links!
build: Ignore _build directories
Merge pull request #330 from hflynn/rebased/develop/format_links

Fixing links to new formats docs (rebased onto develop)
Merge pull request #331 from rleigh-dundee/updateignore-develop

build: Ignore _build directories (develop)
Fix Readme to account for doc reorganization
Fix Makefile options section
Fixes as per Mark's suggestions
Improve wording of top-level Makefile description
Additional fixes
Merge pull request #333 from sbesson/rebased/develop/10687_README

Fix readme (see #10687) (rebased onto develop)
Adding FLIMfit to products & docs menu