Merge branch 'master', remote branch 'origin'
MultiDict and HeaderDict cleanup and speedup.

api: MultiDict.[iter]items() now returns all items. iterallitems() is obsolete.
Added 'filter' method to HeaderDict to filter out a number of headers.
Added HeaderProperty.
The Response.COOKIES attribute is deprecated now.
Added `Response.status_line`, `Response.status_code` and `Response.code`,
which is currently an alias for `Response.status`. In future releases,
`Response.status` will return a string (e.g. '200 OK') instead of an integer.

To make the transition as smooth as possible, you should use the verbose
attributes from now on. I will deprecate `Response.status` in 0.10 and
re-introduce it in 0.11 with the new behaviour.
Reverted parts of 937328 and fixed MultiDict for py3k.

MultiDict now behaves exactly like a dict.
docs: Split Request() and Response() API into sections and removed dublicate
      AppStack API.
Added a helpful error message (ImportError) to json_dumps if no json library
is available (python 2.5).
Splitted Request into [Base/Local]Request. Same with Response.
Added BaseResponse.script_path property.
Reordered BaseRequest() and updated some of the docstrings.
Moved MEMFILE_MAX from module level to RequestBase.MEMFILE_MAX.
Prepared BaseRequest for its new role.

It can now store a body and has a more flexible status attribute.
Solving #164 documentation bug.
Merge pull request #166 from iurisilvio/master

Solving issue #164
Whitespace.
Added BaseRequest.query property as an alias for .GET.
BaseRequest.path and .method are properties now.
Deprecated BaseRequest.COOKIES in favour of BaseRequest.cookies.
Reordered BaseRequest methods to get a better ordered documentation.
Added and fixed a lot of docstrings.
Added 'remote_route' and 'remote_addr' properties to BaseRequest.
Added 'REMOTE_USER' support to 'BaseRequest.auth'.
Lots of docstrings and some tests.
Due to popular demand: Added BaseRequest.json property.
Typo
Fixed some Python 3 issues.