Add possibility to disable performance Optimization when exporting and printing

Description

1. Add possibility to disable performance optimization during print. So the curves look much better on export and print
2. Increase the numberOfPixelX value by factor 10. So even when zooming into the pixmap no artifacts of the vertical lines is visible

Conformity

• Changelog entry
• Unit tests
• Update INSTALL
• Downport
• Fixes: #917 (closed)

When external dependencies are removed

• Reporting to ...