Revised version of Android UI component operator
Drop use of WeakReferences and use a custom subscription instead
update TODOs according to meeting
Drop volatile in favor of failing fast if not subscribed from UI thread
Only release references in unsubscribe

We decided it's better to leave it to the caller when it's appropriate to release, cf. #1
Add guards around log statements
Remove isFinishing check when calling back to activities

We decided it's sufficient for the callback to be safe as long as the caller unsubscribes in onDestroy
SerialSubscription and Timeout operator
SerialSubscription and Timeout operator
Improved efficiency of SerialSubscription and unit tested Timeout
Fixed a couple of warnings and reverted change to imports
Fixed the issue that 'take' does not call 'onError' when 'onNext' throws any error
Fix OperationSwitch so that it does not onComplete() before inner and
outer subscription completes.
Fix OperationSwitch so that it does not onComplete() before inner and
outer subscription completes.
Do not unsubscribe from child once parent has been completed.

Child should not be unsubscribed when the parent complete because it may not be completed.
Caching the result of 'isInternalImplementation' so that reflection doesn't get invoked on every subscribe
Merge pull request #441 from zsxwing/issue-417

Fixed the issue that 'take' does not call 'onError'
Merge pull request #443 from ylecaillez/master

OperationSwitch notify onComplete() too early.
Merge pull request #434 from johnhmarks/Timeout

Implemented SerialSubscription and Timeout operator
Merge pull request #447 from mattrjacobs/internal-impl-cache

Caching the result of 'isInternalImplementation'