Java 955 - Throw exception when DB name contains spaces
Added Test Cases/ Refractoring
Moved DB Name validation logic / Removed Null check as it already throws NullPointerException
Updated Error Message
optimized imports
Updated Test Cases
Reusing cleanupMongo
Reusing cleanupMongo
Resoved merge conflicts
reverted old test
Merge branch 'java955fix' of https://github.com/mohansingh0141/mongo-java-driver into mohansingh0141-java955fix

Conflicts:
	src/main/com/mongodb/DB.java