Django sessions TTL support
Fix docs quotes
Added regression test for numerical string keys.
Fixed #238: dictfields handle numerical strings indexes.
fix travis build: builds were failing because libz.so location changed.
Fix for issue #237: clearing changed fields recursively in EmbeddedDocuments after saving a Document
Add testcase for issue #237
Changed dereference.py to keep tuples as tuples
added unit test for dereference patch
Added LongField to support 64-bit integer type.
Added test cases for LongField.
Fixed potential overflow error.
ReferenceField query chaining bug fixed.
Revert "Fixed potential overflow error."

This reverts commit 67182713d96233d3d2feb0f67d39ddaf1789c692.
add myself to AUTHORS
QuerySet chaining test was supplemented with ReferenceField
chaining test
only mark a field as changed if the value has changed

Prevents spurious changes from being recorded.
explicitly check for Document instances when dereferencing

In particular, `collections.namedtuple` instances also have a `_fields`
attribute which confuses the dereferencing.
more ordering unit tests
show that order_by followed by limit works, but not the other way around