Add step DebLintian

Check debian packages for common problems.
Add DebPbuilder step.

This step buils a debian package inside a pbuilder chroot.
Improve steps.packaged.deb

Add Cowbuilder support and more options for Pbuilder and Lintian.
Add some documentation for dep steps.
Some bugfixes.

Add buildbot.steps.package.dep to install list.
Add components to UbuPbuilder.
No default distribution for Ubuntu subclasses.
Add support for codebases to ForceScheduler (and multiple codebases)

* a new NestedParameter type to encapsulate 'child parameters'. This is helpful where a certain field needs to be present multiple times on a form and have a unique name each time. For example, each codebase needs a 'branch' field. A nested parameter curries the name of the subfields so that the form submission names are unique (foo_branch and bar_branch). Then, after a POST, the names are un-curried and subfields become keys in a dictionary (for example, foo={'branch':'...'}).

* AnyPropertyParameter is now a NestedParameter

* CodebaseParameter is a new parameter (NestedParameter) that converts its children into a sourcestamp dictionary instead of a property value

* The form HTML is adjusted to make it easier to customize the look of the form. Nested parameters can now be grouped using borders, adjust linebreaks (for example AnyProperty has no break between name/value, but CodebaseParameter has breaks between its fields).
Add optional start callback to GerritStatusPush
Set Cache-Controll header for log files in WebStatus. (Fix #2292)
Fix up CSS and other minor bugs
Merge branch 'log_cache' of git://github.com/jiuka/buildbot
Maintain locks in FIFO order

Locks should be kept in a queue in FIFO order to prevent potential
exclusive lock holders from being starved by a continuous stream of
counting locks holders.

This change maintains order of all waiters in a FIFO queue until they
actually acquire the lock, instead of removing them from the queue on
wake and adding them back to the end if they failed to acquire the lock.

The Deferred instance associated with each waiter is cleared when it is
woken. It is set when waitUntilMaybeAvailable is called.
Ensure that locks are acquired in FIFO order

To prevent starvation, locks should be acquired in the order in which
they were requested. Particularly, counting locks requested after
exclusive locks must wait until after the exclusive lock is acquired
and subsequently released, even if the owner(s) at the time the lock
is requested are counting and below maxCount.

The test acquires a counting lock, and then starts a build needing an
exclusive lock followed by a build needing a counting lock. The first
counting lock is then released, and the test checks that the exclusive
lock was claimed before the second counting lock.
Merge branch 'nostarve' of git://github.com/jstultz/buildbot
fix for py25, where next() isn't defined
Nicer directions for finding release notes
Add docs and docstrings for ForceScheduler+codebases
CodebaseParameter: Add customization point for sourcestamp creation
Fix up HTML and CSS to remove extraneoush BR's
Add start callback to GerritStatusPush docs

Documentation updated, and mentioned in release notes.