V 0.3 beta 10 (Fix sampling offset bugs and fix clipping in EGA 640x350)

Bug fixes:

• Fix the sampling offset bugs (including the CGA and MDA ones) introduced by beta 9. Many thanks to @Bs0Dd for the bug report and fix!
• The horizontal clipping in EGA 640x350 should now be fixed. We can now use higher sampling offset values up to 25.

Interface change:

• When in pixel clock mode long-pressing now changes the pixel clock by 1 KHz. This makes it easier to try different frequencies now that we have too many sampling offsets to choose from.