Made tests conditional on the installed status of tuxguitar.

Reworked the tests to check whether tuxguitar is installed.  Based
on that check, did not run tests that depend on it being installed,
and printed a message on the console advertising that fact.

Added back the updatePackage() test since that check was already
being made.
Made tests conditional on the installed status of tuxguitar (II).

Checked that tuxguitar is in fact installed prior to running the
'remove' test.  If not installed, prints a message on the
console to that effect, and does not run the 'remove' test.
Fixed jshint errors.
Tests require fewer assumptions about initial conditions.

Used 'glib2' for searchPackage() test and '/usr/bin/ls' for
searchFiles() test since they exist and are installed.

Modified searchPackage() "installed" vs. "~installed" tests
basing them on whether tuxguitar is installed or not.

Rearranged and general cleanup.
Improved nodepackagekit implementation and unit tests.

- nodpackagekit.cc: Retrieves architecture info from the package
id and stores it in the new "arch" field of the package JS objecgts.

- nodepakagekit_test.js:  Uses "arch" field to match package
across the install/remove tests.  Also, made the assertX() messages
more generic.
Fixed searchPackage() and getPackages() tests.

Used new "arch" field to insure that the package that is checked
for in the 'installed' or 'available' lists takes the architecture
information into account.
Merge pull request #11 from klown/device-reporter-draft2

Latest changes on nodepackagekit_tests.js