fix: A slave should be shut down only if idle and
DEFINITELLY NOT after loosing the connection to the master
due to network problems or the slave process crashing.
Add property to Job/Project configuration to allow per-job snapshot definitions.

A job level snapshot overrides a node level snapshot.

Squashed commit of the following:

commit 642c90fefe7af1dbac2f8e1d0bbf1611e89b18af
Author: Alex Szczuczko <alex@szc.ca>
Date:   Mon Aug 12 11:41:19 2013 -0400

    Polish snapshot job property

commit b77d59cd9bdb69a83ad703712e98b56f08efb9bc
Author: Alex Szczuczko <alex@szc.ca>
Date:   Fri Aug 9 15:24:43 2013 -0400

    Add JobProperty to hold per-job revert snapshot data.

commit 2e8d23d4a4407a3b3d9e97c8b9dd0e32f591abb2
Author: Alex Szczuczko <alex@szc.ca>
Date:   Fri Aug 9 15:15:04 2013 -0400

    Move jobBeforeJobSnapshotName init to increase clarity

commit 5c0034cf5b72460364410cfc0ab621086ffae90c
Author: Alex Szczuczko <alex@szc.ca>
Date:   Fri Aug 9 12:30:20 2013 -0400

    Fix generic types

commit 5767bb798e4f32af5b3ed6ec0564a7ba0308d428
Author: Alex Szczuczko <alex@szc.ca>
Date:   Fri Aug 9 10:13:55 2013 -0400

    Prepare LibvirtSnapshotRevertRunListener to accept more than one source of a snapshot name

Conflicts:
	src/main/java/hudson/plugins/libvirt/LibvirtSnapshotRevertRunListener.java

Signed-off-by: Nigel Magnay <nigel.magnay@gmail.com>
Add some .gitignores

Signed-off-by: Nigel Magnay <nigel.magnay@gmail.com>