unique_case_insensitive attribute
removing the 'feature' that you couldn't AND queries together using the same field constraints.  For example qs.filter(x=1) qs.filter(x=2).
Dummy commit.
remove the deprecated mongoengine/base.py
ensure proper default write concern
merge children of the same type + dont do _cls $in for a single subclass
Merge branch 'simpler-cls-query' into closeio