Allow user to pass "args" argument to the ScriptDeployment class. This
argument tells which command line arguments get passed to the
ScriptDeployment script.

Part of LIBCLOUD-394.
Change wording in the changes file.
docs: Add "developer information" TOC to the documentation index page.
docs: Add examples which show how to create a record with a custom TTL and
record with a priority.
Update libcloud.compute.deployment module docstrings.
Also allow user to pass "args" argument to the ScriptFileDeployment class.
Moar love to the deployment classes docstrings.
docs: Add deployment chapter to the documentation.
Fix a typo, some rewording.
docs: Use a better bootstrap example. Previous one wasn't really clear what was
going on and it looked more like a single command was executed on the server
instead of a whole script being run.
docs: Link to the deployment page from the compute index page.
Unify argument order in crate_node: AWS, OpenStack
Add ex_metadata parameter to create_node
Set Content-Length to 0 only if it is not set