Speedup build by moving insight zip targets to release-clients

Previously, the insight component was calling "dist" during
the "package" phase which meant that a number of zips were
all created in a phase when most other components were just
building a .jar. Now, "dist" is only called by the special
"zips" target, which is in turn called by the top-level
"release-clients" target (as in docs/hudson/OMERO.sh).

"zips" targets may should be added to all components to all
producing releasable artifacts in addition to the basic
artifacts.

This change was made in order to have a unit-testable build
that does not timeout on travis-ci.org.
Add top-level `release-all` target

With a little re-arranging, all the release
targets are now callable via a single target
(the order is important!)
Remove UNSIGNED build logic

Previously for supporting webstart, all jars were
being first generated as name-UNSIGNED.jar and
then signed to the official name name.jar. Then,
they were being re-signed during the webstart
phase. In order to speed up the job and reduce
disk usage (for travis) this logic has now been
removed.
Delay creating matlab.zip until release-clients

The matlab distribution is significantly large that
it makes sense to only build if it is requested.
Make 'test' of /specification a no-op

Apparently, there are no longer any unit
test classes in this component so that the
top-level "test-unit" target was failling.

A better strategy is likely to put true
unit-test like activities (schema validation,
etc.) into this target.
Skip signing most jars on update

Since only the jars under lib/insight are now signed,
calling signjar for dist/lib/server/blitz.jar et al
causes server start-up to fail.
Merge pull request #632 from joshmoore/rebased/develop/build-speedup

Build speed-up (rebased onto develop)