refactor System.[g/s]etProperty(...) calls.  instead use MasterConf .[g/s]etProperty(..) calls.

This pull removes environment variable handling from the code.  It does not move the existing System properties to config files (left for next refactor).

Everything is funneled to the MasterConfig class which uses Utils.getProperty(..) setProperty() to change properties.  The property weight is maintained for both get and set:  system > .properties > hadoop config
Should these be added as constants to *Conf to comply with the current pattern?