Merge pull request #1 from OpenPIV/master

a long list of fixes
fixed long-standing bugs of selection region and selection of columns and rows due to the fact that some data was shown upside down
the default ydir now is reverse. we need to think of how to make it both pleasant and consistent
added the long requested feature of the last file path - every new load opens the previous location
Merge pull request #3 from alexlib/master

Two bug fixes