* support OrderedDict
* support uniq indexes
* support positional operator $ for $set operation
* unittests for fixes
* setup fix for importing OrderedDict
* support sort in find_and_modify
* avoid original data modification if send as link in $set
* $ne in filtering nested structures
* fixes in tests for python 3
* fixes in tests
* fixes for  tests
Merge pull request #113 from golem131/fixes

Some fixes