Fix for issue GPII-8

GSettingsHandler appears to core dump when trying to set a non-existent
key in a schema (see http://issues.gpii.net/browse/GPII-8)

The problem is that Gio.Settings segfaults when requesting a
non-existent key from a gsettings schema.

This fix checks if the setting matches with the gsettings schema before
each set/get.
Avoid USB drive event handler from getting more than one mount points

see http://issues.gpii.net/browse/GPII-95
Adding the GPII Orca Settings Handler
Setting startingProfile in user-settings.conf
Use XDG_DATA_HOME if exists or use the default one

see
http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html
code-style: homogenizing the use of quotes
Adding support for nested JSON objects
Now we're restore settings properly
Merge remote-tracking branch 'javihernandez/GPII-8' into GPII-8
GPII-8 Adding unit test for fix.
GPII-78: USB Listener for Linux is unresponsive

see JIRA: http://issues.gpii.net/browse/GPII-78

Removed the "partition number" restriction from the GPII's udev rule.
Using path.resolve to build paths
Using fluid.registerNamespace for setting gpii.orca
Code cleanup
Code cleanup
Merge remote-tracking branch 'javihernandez/GPII-78_2'

* javihernandez/GPII-78_2:
  GPII-78: USB Listener for Linux is unresponsive
rc and sync working version of the Orca Settings Handler

  - Using gpii.getJSONFromFileSync
  - Simplifying some stuff
  - Code clean up
Adding some unit tests
GPII-116: added support for kettle.
GPII-116: updated tests. gsettings tests use depricated setting paths. need to be updated.