Set operations are indepenednt on implementation.

However, when our in case of our implementation , optimalizations are used.
Splitted speed benchmarks to Read/Write
Grouped Read/Write benchmarks
Benchmark compilation to 'build' directory
Map union/intersection no longer needs PersistentMapImpl
Map union/intersection tests
Merge remote-tracking branch 'origin/master' into fix_union_intersect

Conflicts:
	lib/src/set.dart
	lib/src/set_impl.dart
Moved PersistentVector#iterator implementation
Merge pull request #39 from vacuumlabs/quick_fix_vector_iter_impl

Moved PersistentVector iterator implementation
Merge remote-tracking branch 'origin/master' into benchmark

Conflicts:
	benchmark/vector_speed/benchmarks.dart
Merge pull request #38 from vacuumlabs/fix_union_intersect

Fixed union/intersect implementation depenedency
Merge pull request #35 from vacuumlabs/benchmark

Splitted speed benchmarks to Read/Write
Merge remote-tracking branch 'origin/master' into tests
No msgs when running all tests
Moved basic tests to map tests
Map test in unittest interface