Release Name: 0.2.0

Notes:
CSSpool (pronounced "cesspool") is a validating SAC parser for CSS.  The parser
calls methods on a document handler depending on what it has found. CSSPool
currently only supports CSS 2.1.  CSSPool will not yield invalid properties or
selectors.


Changes:
== 0.2.0

* Added CSS::SAC::Parser#parse_rule to parse a single rule.
* Added CSS::StyleSheet#find_rule for finding a particular rule.
* Added CSS::StyleSheet#rules_matching for finding all rules matching a node.
* Added CSS::StyleSheet#create_rule for creating a new rule.
* Added CSS::StyleSheet#find_all_rules_matching for finding all rules that match
  any node in the passed in document.
* Added .eql? to selector AST
* Added .hash to selector AST 
* Added .eql? to LexicalUnits 
* Added .hash to LexicalUnits 
* Added CSS::StyleSheet#to_css
* Added CSS::StyleSheet#reduce!
* CSS::StyleSheet is now the default document handler