objectquery: add comment to explain 507 response
objectquery: fix content length mismatch cases

Previously, we only checked if the content-length header was not equal
to the amount of content received in a request. This resulted in a "499
Client Closed Request" (indicating a premature disconnect).

This response could be triggered by content either less then OR greater
than that specified in the conteint-length header. This is a bit weird.

This change alters the check and breaks it into two cases:

- actual content < content-length: 499
- actual content > content-length: 400 (Bad Request)

Tests are updated accordingly.
objectquery: 405 if container req is not GET

Containers can only be read by ZeroVM applications, thus "GET" is the
only supported method.

Previously, anything that wasn't a GET on a container resulted in a "400
Bad Request".
force usage of get_response in objectquery tests

most objectquery tests were using direct call of `zerovm_query()` which was not testing the whole pipeline
changed all tests to use a proper call to middleware app through `get_response()`
Merge pull request #138 from pkit/tests_fix

force usage of get_response in objectquery tests
Merge pull request #134 from larsbutler/zerovm_query-bugs

`zerovm_query` HTTP responses: bug fixes and clarification
vagrant: fix a typo/bug in swift config
vagrant: set up `demo` user credentials

This makes it easier to use swift/zerocloud as either `admin` or `demo`.
vagrant: separate admin and demorc files

For testing zapps with multiple users, it's useful to have separate
environmental config files.
Merge pull request #140 from larsbutler/vagrant-minor-tweaks

Vagrant: minor tweaks
move some exception handling to a better place

HTTPExceptions should be handled in the outmost callable
that way it's easier to catch all the exceptions that may arise anywhere in objecquery code
strategically moved all the debug logging and exception handling into `__call__` method of the middleware
improve objectquery log line

use standard Swift logging facility
add more info to the log line
Merge pull request #139 from pkit/minor_fixes

move some exception handling to a better place
Merge pull request #141 from pkit/logging

improve objectquery log line
add better description for API setup

added entry to docs that describes setup of `/api/...` entry point.
resolves #142
Merge pull request #145 from pkit/doc

add better description for API setup