cleanup

Just some clean up stuff including:
- removing unnecessary imports (some of the imports for classes were changed to single class imports, even though i prefer it that way, but tried to avoid doing this as it would make the diff messier, but sometimes it still happened due to my IDE)
- removing unnecessary casting
- removing unnecessary logic checks
- removing unused variables
changed statement to queryStatement in this commit https://github.com/anhsu/odo/commit/45cc3e8d8632fd1390b5c535b7d39d60f30b952a