Minor fixed

- No new features
- Applied some patches from HashBucket to SetBucket
- Removed unused code in QueueBucket, HashBucket, SetBucket
- Fixed exception message in Bucket
- Fixed HashBucket.csproj (not sure why didn't get in in last commit)
Code style: whitespace fix
Static field in generic type -> non-generic type
Renamed non-generic type Bucket to BucketHelper
Moved BucketHelper to a new file
Moved BucketHelper to a new file (updated projet)

- Now I know I missed that the last time