Imported all the legacy codebase

Change-Id: I5da477413a714429a0735cc2701824eb71f689f2
Merge branch 'legacy-import'
Initial Properties based Preferences implementation, with both native
Properties and XML Properties backends. 

Needs Node removal implementation, validation of the synchronization
constructs, performance improvements (batched flushes?), unit tests

Change-Id: I858bd6d2a768373fad4009ade6dc6d977bff44fb
Fleshed out a bunch of the comments and cleaned up a couple of items. 

Still need: efficient sync'ing & flushing, unit tests, logging, a
"create immediately" setting, and research/testing of the
synchronization components

Change-Id: I78ff49d4b336f6db1202664bc12bf9894bce91f3
Some minor improvements and changes to verify proper function with the
application.

Change-Id: I211b80203692d517299f652eabd7f14c29b84878