support for preferences tags

This adds support for variable preferences so that they are properly
injected into the config.xml
[JBIDE-15843] better feature removal

Changes the removal of feature tag from config.xml so that the tag is
removed toghether with its descendant nodes on the first encounter. Also
makes a change to on the PropertiesPage so that it resets the parameters
view when the features are removed.
Handle missing plugin name

Handles the case when a Cordova plug-in does not properly define a name
JBIDE-16065 relabel feature as Technology Preview instead of Experimental
[JBIDE-16053] add the App plugin to default template

add the built-in App plugin to default config.xml template
Merge pull request #20 from nickboldt/JBIDE-16065_master

JBIDE-16065 relabel feature as Technology Preview instead of Experimental >> master
Merge branch 'master' of github.com:jbosstools/jbosstools-aerogear
[JBIDE-16081] change dependency to luna compatible
Merge branch 'master' into jbosstools-4.1.x