adding masked resource functionality so that sensitive properties can be masked from the admin console (and REST service)
Merge remote-tracking branch 'upstream/master'

Conflicts:
	karyon-admin-web/src/main/java/com/netflix/adminresources/resources/PropertiesResource.java
added property masking.  added appropriate unit test.
Merge pull request #40 from cfregly/master

added masking to hide sensitive properties and environment vars in admin webapp