Implement additional error handling in utils.import_object function
Merge remote-tracking branch 'upstream/master' into import-object
import_object will raise standard ImportError even in case of Value/Attribute error
Adding support to override, via static_url, whether the generated URLs
should include the version signature or not.
Introduce StaticFileHandler.(get_content|set_headers) which reduces the
complexity of the HTTP GET handler of static resources.
Fixed syntax error in the altered StaticFileHandler.get() method
Move retrieval of absolute path to separate method which is also in
charge of validation.
Cache the computed absolute path to the requested resource in
StaticFileHandler. The cache is cleared on_finish of each request
in order to ensure recomputation on each request.
Add ability to get/set HTTP response reason phrase in RequestHandler and HTTPResponse
Do not remove empty GET/POST parameters
Add concurrent.futures as an optional dependency for -full builds
Add IOLoop.add_future to return to the IOLoop after a future has completed.
Add futures-based Resolver interface, and test with both sync and thread pool.
Capture stack_context in IOLoop.add_future
Use new async resolver interface in simple_httpclient.
Improve autoreload for import-time errors.

We already had a special case for SyntaxErrors, but NameErrors and other
import-time errors could leave a file unwatched.
Flesh out future-oriented client interfaces.

Make DummyFuture a more complete imitation of Future.

Add tests demonstrating various implementation styles.

Add a decorator that simplifies use of futures.
Add gen.YieldFuture.
Add magic for yielding futures.

Introduce IOLoop.current() as a thread-local counterpart to IOLoop.instance().

gen.engine now recognizes Futures directly.
Merge branch 'master' into futures