Version 0.3.0

Implemented features and fixes:

• Fixed subtle misalignment between point histogram bars and their points #122 (closed)
• Continue with import of spreadsheet if empty rows inbetween #127 (closed)
• Rename files tab to exam #125 (closed)
• Allow open passing limit of up to 60% total open points #124 (closed)
• Accept both dynexite files with commas and dots as decimal separator #121 (closed)
• Grade boundary heuristic returns wrong result if grade boundary step <1 #120 (closed)
• Point histogram x axis unit #116 (closed)
• Export grading scheme to clipboard #109 (closed)