Implement collapsing margin
Adjust top_offset when top margin of a element collapses with its first child
Add reftest for margin collapsing
Fix android build on Darwin.

This cleans up configure and Makefile.in so that things build correctly on Darwin.
 Generate bindings for HTMLTemplateElement.
Generate bindings for HTMLPreElement.
Generate bindings for HTMLLegendElement.
Generate bindings for HTMLLabelElement.
Generate bindings for HTMLTrackElement.
 Generate bindings for HTMLMediaElement.
Generate bindings for HTMLAudioElement, HTMLVideoElement.
Add testcases.
Convert tagName to uppercase ASCII per spec

http://dom.spec.whatwg.org/#dom-element-tagname
Add style structs.
Handle 'color: currentColor'
Resolve 'unset' to 'initial' or 'inherit' when parsing.
auto merge of #836 : bfrohs/servo/834upperTagName, r=jdm

http://dom.spec.whatwg.org/#dom-element-tagname

I added `window.alert(elem.tagName);` to line 14 of `test_bindings.js` to test (segfault at line 17), and it indeed uppercased the tagName. I didn't add that to this commit, however, because `tagName` is already tested on line 50 of that file. I'm assuming the duplication isn't necessary. Am I correct in that assumption? Or should tests be added somewhere for this? Where?
auto merge of #837 : saneyuki/servo/webidl, r=jdm
Add cascading.
Warning police