Do not read Maq options from servlet environment.

We are no longer making use of the servlet container's
environment (i.e. "context.xml") for Maqetta options.
Instead, we're just reading from maqetta.conf, both for
standalone and WAR builds.
Merge branch 'master' of github.com:maqetta/maqetta

* 'master' of github.com:maqetta/maqetta:
  set response to declare json mime type
  use StringBuffer
  Explicitly check for missing siteConfigDirectory setting #3705 and let handleCommand handle/surface all exceptions.  Surface as HTTP errors for now.  Could pass back error messages in the JSON for the client to handle #3691
  correct indentation