script: Don't do anything before the window size comes in.

This fixes the `getBoundingClientRect()` content test.
Fix parsing of the 'content' property.

Conflicts:
	src/components/style/properties.rs.mako
fix for anonymous block boxes
remove block exception
remove unused import
add comment
fix comment
auto merge of #1461 : ksh8281/servo/block_black_boxes, r=SimonSapin

fix for anonymous boxes.
http://www.w3.org/TR/CSS2/visuren.html#anonymous-block-level
fix try_to_append_line for ImageBox
auto merge of #1463 : ksh8281/servo/img_new_line, r=pcwalton

````
<div>
   test
   <img src="test.jpeg"/>
</div>
````

if reduce window size, img is disapper.
this pr fixes this case.
CSS parsing/selector-matching for pseudo elements
Implement Document::head()

Implementation details according to the specification below:
http://www.whatwg.org/specs/web-apps/current-work/#dom-document-head

This patch is for:
https://github.com/mozilla/servo/issues/1465
auto merge of #1466 : brunoabinader/servo/document-head, r=kmcallister

Implementation details according to the specification below:
http://www.whatwg.org/specs/web-apps/current-work/#dom-document-head

This patch is for:
https://github.com/mozilla/servo/issues/1465

Closes #1465.
Change range to iter() and add comment for FirstLine and FirstLetter
auto merge of #1409 : pcwalton/servo/fix-get-bounding-client-rect, r=jdm

This fixes the `getBoundingClientRect()` content test.

r? @jdm
auto merge of #1464 : parkjaeman/servo/pseudo-element-selectors-matching, r=SimonSapin

CSS parsing and selector matching for pseudo element :before and :after
Remove some trailing whitespace.
Comment out parsing of ::firt-line and ::first-letter, they’re not supported yet.
Make SelectorMap private.
Remove unused PerOriginRules struct.