SendTo MD5 v1.6 + Portable

Changed the threading code to use a single worker thread
Changed the MD5 benchmark output to show more useful and readable info
Removed 'MD5 Benchmark' from the main menu, as it's still not that useful
Trying to close the application while operation is running, will now cancel all operations in the queue
Changed the default highlight colors to be more distinguishable from one another
Fixed a deadlock issue when adding thousands of files to the hash operation queue
Fixed a bug where in rare cases continuing search operation would actually cancel the operation
Fixed a bug where hash search would skip a file if its filename starts with two dot (..) characters
Fixed a bug where canceling a benchmark operation would display an error
Numerous other minor tweaks and fixes