Cpp: Remove C++ links which are no longer available

No alternative or replacement links exist at present,
therefore removing them entirely.
Fix hardcoded links to Javadocs in the developer documentation
Merge pull request #617 from rleigh-dundee/cpp-link-removal-dev50

Cpp: Remove C++ links which are no longer available
Merge pull request #611 from hflynn/rebased/dev_5_0/glencoe_link

Removing link to out-of-date Ice binaries at Glencoe (rebased onto dev_5_0)
Merge pull request #614 from sbesson/rebased/dev_5_0/new_ci_root

Modify the root of the main OME CI server to use ci.openmicroscopy.org (rebased onto dev_5_0)
Split BlitzGateway from Python page
Blitz API 'New in OMERO 5' docs
Fix OMERO.server directory in server upgrade section

- Fix OMERO.server directory name (removing undesired .zip)
- Add recommended symlinking to simplify subsequent steps with
  $ cd OMERO.server
Small fixes from PR #603

Conflicts:

	omero/developers/Web/EditingOmeroWeb.txt
merge dev_5_0 -D org -I include -E exclude: PR 615 (Backwards compatability instructions for web plugins (rebased onto dev_5_0))
merge dev_5_0 -D org -I include -E exclude: PR 619 (Fix hardcoded links to Javadocs in the developer documentation)
merge dev_5_0 -D org -I include -E exclude: PR 620 (Server upgrade bugfix (rebased onto dev_5_0))
merge dev_5_0 -D org -I include -E exclude: PR 621 (Blitz api5 11852 dev 5 0)
merge dev_5_0 -D org -I include -E exclude: PR 622 (Small fixes from PR #603)