Version 0.9.2
Updated ming provider to avoid InvalidId exception

Added InvalidId exception catch to avoid exception raising on wrong _id
Fixed ObjectId cast, added tests
Merge pull request #1 from devilicecream/patch-1

Updated ming provider to avoid InvalidId exception
Merge branch 'master' into development
Merge branch 'master' into development
Add also test case for proper id casting
Take advantage of the IdentityMap cache for get_obj and refactor it