Document Homebrew formula upgrade to 5.0.0

- Remove the `--devel` option to install OMERO 5.0.0
- Simplify the environment variable configuration for Ice 3.5 (default)
- Add environment variable sentence for non-default Ice 3.3 and 3.4
Add directed graphs to document relations between latest BF jobs

This commit is a proof of concept for the usage of the sphinx.ext.graphviz
extension. The latter extensions could allow to insert directed graphs
describing the relationships between CI jobs. Note this proposal would also
impose graphviz as a prerequisite to build the contributing documentation.
Add graphviz dependency to the Travis build
Add a heading and link for search re-indexing

Will need this link for documentation on search trouble-shooting
Add link to OOM and info for other process heaps

This will be linked from the documentation on omero.search.batch
referencing the fact that the heap size may need to be increased if the
batch size is increased.
Add sections for omero.search config settings
Add target to link to IceGrid admin tools

This will be used in the troubleshooting section on the Indexer
Add comment on potentially corrupting search index
Add section on search indexer troubleshooting

This section contains a series of steps that sysadmins should take in
attempting to resolve a situation where search is not returning the
correct results. It also references previously updated/modified sections
on the new search configuration settings and increasing the indexer's
heap size.
Style edits to server advanced config file
Proofing/wording edits to troubleshooting
Merge pull request #684 from jballanc/rebased/develop/11995

Update documentation for search indexer and related troubleshooting steps (see #11995) (rebased onto develop)
See node shape and font size
Set font size to 9
Updated section on search re-indexing (see #11995)
Fix links to Bio-Formats source code post-renaming

This commit should update the source code links to point at the new
formats-bsd, formats-gpl and formats-api folders of the Bio-Formats repository
Merge pull request #687 from jballanc/rebased/develop/11995b

Updated section on search re-indexing (see #11995) (rebased onto develop)
change TeX Gyre font package so XeLaTeX can find it
Merge pull request #688 from sbesson/formats_bf_renaming

Fix links to Bio-Formats source code post-renaming
Merge pull request #689 from mtbc/tex-gyre

change TeX Gyre font package so XeLaTeX can find it (rebased)