Return the default value from getJSToNativeConversionTemplate, to allow reusing it more easily.

This commit does not change the generated code.
Rewrite the dictionary codegen to use pattern matching rather than is_some/unwrap.
Support dictionary members without default values.
Add documentation for Line::{bounds, green_zone}
Remove the need to destructure InlineFragments

We do this by moving InlineFragmentMap::fixup into InlineFragments
Remove last methods from InlineFragmentMap
Remove InlineFragmentMap
auto merge of #2550 : Ms2ger/servo/default-handling, r=jdm
Use destructuring to clean up InlineFragments::push_all
auto merge of #2553 : bjz/servo/remove-inline-fragment-map, r=pcwalton

This simplifies inline.rs and makes things easier to understand.

I've also added some documentation for `Line`.

r? @pcwalton
Eliminate some warnings
auto merge of #2555 : brson/servo/warnings, r=metajack

Depends on https://github.com/mozilla-servo/rust-fontconfig/pull/19, https://github.com/mozilla-servo/rust-harfbuzz/pull/21, https://github.com/mozilla-servo/rust-hubbub/pull/23, https://github.com/mozilla-servo/rust-layers/pull/68, https://github.com/mozilla-servo/sharegl/pull/29, https://github.com/mozilla-servo/rust-mozjs/pull/85.
Update web-platform-tests expected results.
Order of firing events
auto merge of #2526 : Manishearth/servo/event-order, r=Ms2ger

For the wpt test [event_load](https://github.com/w3c/web-platform-tests/blob/master/XMLHttpRequest/event-load.htm)

Blocks #2525
Remove needless '&mut self' from WindowMethods.
Remove needless '&mut self' from DocumentMethods.
auto merge of #2556 : Ms2ger/servo/update-wpt, r=metajack
Move WebIDL unions into their own module.

This will allow multiple unions to contain the same type.
auto merge of #2558 : Ms2ger/servo/mod-unions, r=jdm

This will allow multiple unions to contain the same type.