Add range mongoization from hash

[ fix #3088 ]
Add support to exclude range

[ fix #3155 ]
Update moped dependency
Flag upserts as persisted.

[ fix #3159 ]
Replace deprecated stub with double
Remove uses of deprecated raise_error with class
Bump to rspec 2.14
Add overwrite option to field definition

When overwrite is true, you may redefine a field without warning or exception
(in case duplicate_fields_exception is enabled).

[ fix #3140 ]
:scissors:
Update changelog
ManyToMany handles primary_key option
Update changelog
make DocumentNotFound simpler to initialize

[fixes #3198]
Fix rake db:mongoid:drop_undefined_indexes

in fact, rename to remove_… for consistency, and deprecate the old name
remove drop_undefined_indexes deprecation
extracting persistence options
removing delegate from sessions
use class persistence_options when init document
adding proxy for better persistence_options on class level
small code cleanup