resolve UnderFS hostname in loadufs, add methods in tachyon.util.CommonUtils and unit tests
resolve UnderFS hostname before using in loadufs
some minor code style fixes
Improved rename

Made it more thorough and use the new InodeFolder structure.
Removed null check for getPath in rename
Created _rename method, which allows EditLog to replay rename without
logging
Fixed inner _rename method
Improved delete method

Modified it to use the new InodeFolder structure better. Also made the
edit log call to delete use a non-logging version. Also put
traverseToInode in alphabetical order.
Removed the extra delete methods

They weren't necessary
Added comments for exceptions in _rename
fix problems with empty prefixes
Small fixes to _delete
Modified delInodes to use ArrayList rather than HashSet
Moved checkpoint deletion before InodeFolder deletion
Removed succeed variable in _delete
Fixed _rename and added @throws to CommonUtils javadoc
not using com.sun.tools.javac.util.ListBuffer, code cleaned up
Made rename return a boolean rather than throw exceptions
fix test cases to cover empty and null, and resolveHostName
fix resolveHostNameTest