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
digest authentication
Fix options.parse_config_file on Python 3.

Add a test for this function.

Closes #702.
Update pypi description field.
Replace the outdated README.md with a lightly-edited version of docs/index.rst
Fix rst markup in readme
Fix another broken link on readme.
Downloads are now hosted on pypi instead of github.
Finalize 3.0 release notes.
Set version number to 3.0
Pypi's rst rendering doesn't like it when the same anchortext is reused
for different targets.
Bump version number in the master branch