Abstracted a text region into the Region type
Abstracted brackets in text into the Bracket type
Abstracted bracket scopes into the Scope type
Abstracted colorable regions into the ColorableSpan type
Removed obsolete code, cleaned up imports
[minor] Fixed stupid bug in make_enum usage
Imposed partial ordering on Regions and ColoredSpans

Only __lt__ (<) and __le__ (<=) are implemented as this is not a total
order. Also thrown in some __repr__ implementations useful for debugging.
Merged branch 'proper-types'

[x] types

Next: actual scope coloring.