erorr responses handled properly

http://susestudio.com/help/api/v2/general.html
sinon stubs gone (mocks remain)

they would probably be useful in more object-oriented
code, but studio_napi is mostly functional, or in
javascript, and studio_napi is in coffeescript, with
very concise function literals.
sinon mocks are very useful thanks to expectations,
stubs were just overly clever for no good.
tests for tests/tools#contains
first step towards end-to-end tests

mocha only reports globals introduced inside `it` (in the BDD
interface, the others are surely the same in this regard).
so far, the HTTP verbs from lib/lo/common.coffee were not
reported because the file is require()d in the top-level
scope first (tests/lo/100-rpc.t.coffee).

this is the first time the HTTP verb helper functions are
actually introduced inside `it`, hence the change in the mocha
command line options.
e2e test for GET /admin/about
e2e test for GET /admin/active_users

turned out the response transformation needed
some tweaking: the example xml file was obsolete
and/or not showing enough;
the new fixture was acquired from my development
instance.
e2e test for GET /admin/health_check

plus a fix for lib/lo/admin#runners, which needs
some more investigation
e2e test for GET /admin/running_jobs
e2e test for GET /user/account
e2e test for GET /user/api_version
e2e test for GET /user/appliances/:app, limited
e2e test for GET /user/appliances/:app/status, limited

only the error response case is tested, there's some
forward-looking unreachable code for now.
e2e test for GET /user/appliances
e2e test for GET /user/builds/:bld, limited

again only error case with unreachable code
for the happy path.

/user/builds/:bld xml2pojo transform updated.
tests/lo/100-rpc.t.coffee dried up a bit
querystring support in the low-level interface

http://nodejs.org/api/querystring.html fails to mention
which spec it purports to implement, testing shows it's
more RFC 2396 than RFC 3986.
tests for the HTTP DSL functions from lib/lo/common
response transforms dried up a bit

`runners` helper from lib/lo/admin renamed to `to_array`,
pulled into lib/lo/common, used in lib/lo/user as well.
e2e test for GET /user/builds?appliance_id=:app

for now, only missing_appliance_id and invalid_appliance_id
cases are tested, there's disabled test for the happy path.
NOTES: (weak) progress on the enable_networking front