Take care of 403 Forbidden HTTP error

Return AccessDenied error to client
instead of default InvalidURI when subsequents
request in pipeline return 403 error.
Fixes for canonicalize_url, object ACL query, signed URLs
Issue #49 - fixed Date and ExpireDate checking logic
Cleaned up PEP8 and Flake8 formatting errors.
canonical_string refactoring + fix typing in middleware comment
Merge pull request #53 from vitoordaz/master

canonical_string refactoring + fix typing in middleware comment
Undo part of patch by Willys

A regression in tests was introduced by commit
12163092ab793c6d0a1b2883f5e1858b97991e22, intended to
fix issue #49.

Willys' code actually seems to make sense, but I chose
to undo it because
 - It appears to be extraneous to the issue #49
 - It does not fix the tests or remove the now-unused constant

Someone should re-fix it properly. But for now I prefer tests
continue to pass.
Merge pull request #54 from zaitcev/master

Undo part of patch by Willys
Add a error of EntityTooLarge

This fix makes to return 'EntityTooLarge' response,
when the object which user try to upload exceeds the maximum
allowed object size of swift.

Signed-off-by: Kota Tsuyuzaki <tsuyuzaki.kota@lab.ntt.co.jp>
Merge pull request #55 from bloodeagle40234/add_entity_too_large_error

Add a error of EntityTooLarge
fix signature generation

In canonical_string, query string must
be lexicographically sorted by query name.
This patch enables to work it correctly,
and adds a unit test for checking it.
Merge pull request #56 from bloodeagle40234/fix-signature

fix signature generation
preven double-quoting object name
Merge pull request #57 from vills/fix_quoting

prevent double-quoting object name
fix requests without object_name
Merge pull request #58 from vills/fix_quoting

fix requests without object_name
Merge remote-tracking branch 'upstream/master'

Conflicts:
	swift3/test/unit/test_swift3.py