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.
update the statement of testing if a handler is a list or tuple
Add hooks for HTTPClient and HTTPConnection customization.
digest authentication
add check for ssl.CertificateError
websocket_connect: don't hang on HTTP errors
tests: test for websocket_connect failure
Add future interface to FacebookGraphMixin
Merge pull request #720 from wsantos/facebook_future

Add future interface to FacebookGraphMixin
HTTPResponse.request should always be an HTTPRequest, never a _RequestProxy.

Closes #718.
Merge pull request #704 from chrislea/master

Add check for ssl.CertificateError in netutil.py
Add 3.0.1 release notes.
Update debug mode docs.