Merge pull request #660 from sbesson/rebased/develop/pillow

Update documentation to use Pillow instead of PIL (rebased onto develop)
Users & sysadmins update text
Updating developers & users whatsnew
Adding JB's sysadmin search stuff
Emphasize omero_prefix over omero_home
Add new page for omero_home recommendations
Cross-reference the new omero_home page
clarifying 'OMERO_PREFIX' in install doc
Style & proofing edits & clarifying OMERO_PREFIX
Fix rst role name typo
Fix spelling
Clarify 64 bit python docs
Remove PyWin32 readme link

It goes via an adverts page, and is auto displayed on the downloads page anyway.
Add note about 64-bit ice paths
Hypenate 32/64-bit
Make it clearer that versions apply to precompiled pkgs.
Other minor fixes.
Update to current usage. Refactor to includes.
Revise basic usage and examples.
Remove extra indentation.
Remove duplicate label