Add a method to generate a DateSpan from a month number
Correctly wrap years
Merge pull request #144 from dimagi/DateSpan_from_month

Add a method to generate a DateSpan from a month number
invalidate dates prior to 1900
Merge pull request #145 from dimagi/invalid

invalidate dates prior to 1900
fix debugdatabase so that it doesn't die on weird keys

(holdover artifact from when it was part of debugtoolbar)
but since we're printing to console, no need to do weird conversions
Merge pull request #146 from dimagi/debug_database_fix

fix debugdatabase so that it doesn't die on weird keys
adding doc_id based helper caches
Merge branch 'master' into couch_cache

Conflicts:
	dimagi/utils/couch/debugdb/debugdatabase.py