- support invisible JobProperty

- simplifying Jelly view and submission handling

refactor the save method so that it is available to all and null safe. also added a readResolve to handle when null properties are deserialized

Adding a TransientComputerActionFactory. Note that the transient actions are never updated, so to make actions appear to be added dynammically you need to always add them and control their display, rather than conditionally add them.  This is the same behaviour as for TransientViewActionFactory but not quite the same behaviour as TransientProjectActionFactory

Conflicts:

	changelog.html

Set M2_Home for maven builds and add maven to the path so if the build
needs to run maven from maven (or maven from ant from maven) it can.

Conflicts:
	maven-plugin/pom.xml
	plugins/pom.xml
	ui-samples-plugin/pom.xml

Otherwise plugin classes won't resolve.