Restructured NSDictionary extension files.
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Skeleton for NSDictionary+MK_Block.
Skeletom for NSSet+MK_Block
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NSSet+MK_Block implementation completed.
Partial test.
NSSet+MK_Block passes tests.
NSDictionary+MK_Block passes all tests.
Commented out test_apply due to its async nature.
Merge branch 'release/0.3.2'