Move context into its own package
Use immutable lists for context matchers
Refactor context matchers to use match elements
Implement context patterns (#47)
Use context patterns (#47)
Remove old element chains (#47)
Add test using pattern matching to resolve infinite wrapping
add missing license headers
Add tests for context match sorting
Sort match elements externally

- Expose type distance from MatchElement
- Sort context matches in two passes
Add additional context pattern test
Make context pattern matching saner
Merge pull request #83 from grouplens/feature/elehack-47-regular-contexts

Enable regular expressions for contexts (closes #47)