Port to Rust 0.6+something, as used in Servo.
Rename stuff.
Remove quirks

They do not belong in Syntax (have been remove from the spec)
and are expected to be defined in Values & Units.
Move AST definitions to an ast module.
At-rules have just a block, not a list of rules or declarations.
Style rule -> qualified rule. Containing any block rather than declarations.
Convert \f to \n during pre-processing.
Name the components of UnicodeRange
Update numeric values to contain the repr and always have a float value.
Move tokenizer tests to work on component values.
Merge tokens and component values.