* Limit training samples size to 2GB
* simplified DISPLAYLEVEL() macro to use global vqriable instead of local.
* refactored training samples loading
* fixed compiler warning
* addressed comments from the pull request
* addressed @terrelln comments
* missed some fixes
* fixed type mismatch
* Fixed bug passing estimated number of samples rather insted of the loaded number of samples.
Changed unit conversion not to use bit-shifts.
* fixed a declaration after code
* fixed type conversion compile errors
* fixed more type castting
* fixed more type mismatching
* changed sizes type to size_t
* move type casting
* more type cast fixes
