Reduced default memory allocation to 4G.
Reduced default memory allocation to 4G.

mapr/shark,alabid/blinkdb,amplab/shark,mapr/shark,mattyb149/blinkdb,sameeragarwal/blinkdb,sameeragarwal/blinkdb,sjyk/sampleclean,sjyk/sampleclean,lzshlzsh/shark,lzshlzsh/shark,mattyb149/blinkdb,mattyb149/blinkdb,alabid/blinkdb,amplab/shark,mapr/shark,sjyk/sampleclean,lzshlzsh/shark,sameeragarwal/blinkdb,alabid/blinkdb,amplab/shark