#2183 Initialize Event::bubbles to false
Increase codegen test coverage.
Implement FromJSValConvertible for union types.
Use FromJSValConvertible's nullable conversion code.
Implement a cleaner way of dealing with optional arguments in codegen and use it for primitive types.

This puts the Some constructor outside the match, making the actual
generating code independent of the optionality of the argument.
Use handleOptional for the 'any' conversion.
Use handleOptional for the union conversion.

Note that unions didn't handle optional arguments correctly before.
Use handleOptional for the DOMString conversion.
Use handleOptional for the enumeration conversion.
Move optional/nullable handling out of CastableObjectUnwrapper.

This puts the code that wraps the type in Option<> and the code that wraps
the expression in Some() into the same if block, which should clarify the
code.
Use handleOptional for interface conversion.
This batch of changes upgrades Servo to work with the Rust upgrade as of
April 10, 2014. The main changes are to privacy, to work around the
issues with incorrect bounds on the libstd `Arc<Mutex<T>>`, and the
various API changes strewn throughout the libraries.
auto merge of #2238 : mozilla/servo/rustup_20140410c, r=Ms2ger

r? @metajack 

Note that all pending submodule PRs must be landed before this should be given r+.
auto merge of #2237 : Ms2ger/servo/union-fromjsvalconvertible, r=jdm

With bonus codegen tests.
Use handleOptional for dictionary conversion.

This does not have any effect, as isOptional is always False for dictionaries.
This change is made only for consistency.
Use handleOptional for callback interface conversion.
auto merge of #2233 : campadrenalin/servo/initialize-event-bubbling-to-false, r=Ms2ger

Fixes #2183.
Throw a TypeError when too few arguments are passed.
Allow passing extra args to wptrunner via an environment variable
auto merge of #2245 : jgraham/servo/make_wptargs, r=Ms2ger