Step 1 of appmaster overhaul

Work for making appmaster more pluggable, container allocator can be
configured via xml. Base work for next overhaul steps.
Step 2 of appmaster overhaul

Work for container launchers. Added better model for launch interceptors.
Step 3 of appmaster overhaul

Changes for container monitor system, how command-line launcher waits
appmaster completion, mods for general listener system.
Removed warnings
Step 4 of appmaster overhaul

Needed changes to batch for reflecting previous changes.