Early Adopter Release #5

Summary of changes:

Pi Firmware:

• Fixed bug affecting test_for_elk()
• Added alternative pixel sampling modes (normal, subsample even, subsample odd, pixel double)
• Added cmdline.txt entry for Oric-1 (tested on Rev's Oric-1)
• Performance optimizations to capture_line_mode7_4bpp.S (Dominic)
• Fix several cppcheck warnings (Dominic)

CPLD:

• No changes, version 2.1 is still the latest version