Merge pull request #125 from prongs/cluster_user_clean

adding cluster user for query execution
Merge pull request #126 from prongs/cluster_user_clean

Fixing small issues
Add service provider api to get instances of various services
Return in case of SemanticException in analyze internal
Merge pull request #128 from jdhok/develop2

Add service provider api to get instances of various services
Review comment incorporated
Updated service provider factory config documentation
Merge pull request #130 from jdhok/develop2

Updated service provider factory config documentation
review comment incorporated
review comment incorporated
Merge pull request #129 from sushilmohanty/develop

throw all exceptions out in ColumnarSQLRewriter
Close result in JDBCDriver.explain
Merge pull request #131 from jdhok/develop2

Close result in JDBCDriver.explain
Merge branch 'develop' of github.com:InMobi/grill into cluster_user_clean

Conflicts:
	grill-server/src/main/resources/grillserver-default.xml
	src/site/apt/admin/config.apt