GEB-174 - correctly read the value of textareas.

Also reworked the tests for form control to make them faster, which highlighted the lack of coverage for this issue.
Make it possible to open the sauce labs tunnel via the build for local development.
Some tweaks to how the sauce browser to use is represented internally.
GEB-251 - standardise on returning "" for attributes that aren't set or don't exist.

Accompanying this is a change to a spec that highlighted this issue when trying to make it work cross browser.
Not needed.
Run this cross browser.
Run these guys cross browser.
Fix error in buildscript.
Remove unneeded test fixture method.
Remove unused code path from when not all driver implementations supported selecting by CSS.
Project update.
Fix construction of the sauce browser system property.