modified core structure
initial version of blist sortedset
forgot dependencies
Merge branch 'master' into feature/blist_collections

Conflicts:
	hot_redis/core/tests.py
Merge branch 'master' into feature/blist_collections

Conflicts:
	hot_redis/core/tests.py
slicing, pickling, eager iterator on by default
Extracted pc serialization to separate methods, so they can be overriden by subclasses that could use different serialization routines
SortedSet now returns items in the right order (low to high)
Moved atoms to core_atoms
First version of zsets intersect_update
Intersect for sorted sets, upgraded tests
Disjoint test and implementation
Added difference_update for zsets
Raising an error for in-place difference calculation
Fixes for mixup with update and non update methods and symetric diff test and stub
Symmetrical difference implementation
Fixed more names mixup
Cmp testing
Slice tests passing through (tweaked tests and constructor - slice creates new instance of the object instead of a list)
Tests for unwanted in place diff methods are asserting the exception