Fixes for BIN / XBIN encoding

[michael-lazar]

This PR resolves a handful of issues, shoutout for @TheGreenHerring for the excellent bug tickets 💯

• Fixes the bug that added two copies of SAUCE in the file when saving XBIN files.
• Fixes "Save without Sauce Info" to actually save the file without SAUCE info.
• Fixes opening BIN files without SAUCE info. This was broken because the default column size was set to be 160 for some unclear reason. Dropping it down to 80 allows successfully opening BIN files that are 80x25 without SAUCE info.
• Fixes the bug preventing saving XBIN files with an uneven number of columns.
• Now shows a warning when attempting to save BIN files with an uneven number of columns, instead of silently failing.

Resolves

#12
#13
#14
#15