Remove unneeded code now that image libraries use Vec<T>.
auto merge of #2387 : glennw/servo/image-fixups, r=Ms2ger
Convert as many of Page's RefCell fields to Cell as possible (fixes #1990).
auto merge of #2390 : Ms2ger/servo/1990-Page-RefCell, r=jdm
Add UIEvent::new_uninitialized().
Add MouseEvent::new_uninitialized().
auto merge of #2384 : saneyuki/servo/2383, r=Ms2ger

Fix #2383

These changes introduce `FooEvent::new_uninitialized()` constructor. This constructor use to create `FooEvent` without calling `FooEvent::InitFooEvent`.

#2383 says integrating `FooEvent::new()` and `InitFooEvent`, but we need to preserve simple `FooEvent::new_uninitialized()` for `document.createEvent()`.

@jdm r?
Remove ScriptTask::initialize_js_info.

There is no particular leason to initilaize js_info lazily.
auto merge of #2393 : Ms2ger/servo/initialize_js_info, r=jdm

There is no particular leason to initilaize js_info lazily.
Remove unused and misnamed url field on HTMLIFrameElement.
auto merge of #2401 : Ms2ger/servo/iframe-url, r=jdm
Rename GlyphIndex->GlyphId

This will allow us to use the GlyphIndex identifier to refer to glyph indexes into text runs in the future.
Add RangeIndex trait and iterator

This will allow for the definition of typesafe range units in the future, for example for glyph indices. This also adds a macro that allows for the easy implementation of new range index types.
Add some trailing commas
Add character index type

This is more self-documenting and may highlight errors in the future.
Add some helpful comments
Use box index type for referring to inline boxes
Fix file mode for servo.rs

For some reason this was set to +x