support consistent mode, synchronized Database
	modified:   Wifi/WifiLocatorTestsTest/project.properties
	modified:   Wifi/project.properties
	modified:   Wifi/src/com/example/Database.java
	modified:   Wifi/src/com/example/RequestTask.java
	modified:   Wifi/src/com/example/WifiLocator.java
	deleted:    Wifi/src/com/example/server/Graph.java