Minor change to a Jinja2 example suite.

The examples/jinja2/defaults suite had (deliberately) a template
variable with no default set, requiring use of the new --set command
line options. However, this broke automated validation of all example
suites.
Repeating asynchronous tasks need instance-specific environment vars.

Recent changes moved [runtime] environment to a class variable, updated
by broadcast (if necessary) at the last minute. So, now also update the
enviroment dict with instance-specific environment variables, if any, at
the last minute. To test run the examples/satellite/ suite.
Trivial documentation update.
Improved release tarball script, via the main CLI.

Uses 'git describe' to generate the release version string.
Merge pull request #208 from hjoliver/jinja2-example-suite-change

Minor change to a Jinja2 example suite.
Merge pull request #209 from hjoliver/satellite-processing-fix

Repeating asynchronous tasks need instance-specific environment vars.
Removed an unnecessary import statement.
Merge pull request #211 from hjoliver/improved-release-script

Improved release tarball script, via the main CLI.
cylc gui: reduce poll of a stopped suite.

Gradual increase of poll delay of a stopped suite.
Note: Because each view is updated by its own thread, destroying a view
will reset the poll delay.
Merge pull request #213 from matthewrmshin/197.cylc-gui-poll

cylc gui: reduce poll of a stopped suite.
Rewrite doc/{process,cleanup.sh} as a Makefile.
doc/Makefile: fix multi/single HTML clash.
Merge pull request #216 from matthewrmshin/doc-make

doc/Makefile to replace doc/process?
Merge branch 'master' into 194-multi-threading

Conflicts:
	lib/cylc/gui/stateview.py
	lib/cylc/gui/xstateview.py