Added OperationRepeat & repeat operator
Added OperationRepeat & repeat operator
Added test
Operations Aggregate, Average and Sum with selector
Operators Skip, SkipLast, Take with time
Remove ObserverBase Import

Was unused and causing build break once that class was removed.
Manual Merge github.com:akarnokd/RxJava SkipTakeTimed2

Conflicts:
	rxjava-core/src/main/java/rx/Observable.java
	rxjava-core/src/main/java/rx/operators/OperationTakeLast.java
Merge pull request #697 from benjchristensen/skip-take-time-merge

Manual Merge of Pull #667
Merge branch 'AggregatorsWithSelector' of github.com:akarnokd/RxJava into pull-657-merge
Remove newly added aggregate methods

- avoiding methods with `index`
- resultSelector overload is same as `reduce(seed, accumulator).map(resultSelector)`
Rename to ReduceTest
Merge pull request #698 from benjchristensen/pull-657-merge

Merge of Pull 657: Average and Sum
Repeat Operator

- merge and slight modification of https://github.com/Netflix/RxJava/pull/518
Merge pull request #699 from benjchristensen/repeat

Repeat Operator