minor fixes on exceptions
Merge remote-tracking branch 'origin/lucene' into lucene

Conflicts:
	wikAPIdia-sr/src/main/java/org/wikapidia/sr/ESAMetric.java
Added a test for phrase similarity
Added pruning
Merge remote-tracking branch 'origin/lucene' into lucene

Conflicts:
	wikAPIdia-sr/src/main/java/org/wikapidia/sr/ESAMetric.java