Easy Mail fixup

This is a somewhat updated version of the Original Easy Mail to fix some issues, as the author has been absent for...well, nearly a decade. No further maintenance is intended (but it seems to happen anyway).

Current changes over the original are listed in file changenotes.

notable features:

• planar fragments are handled better (better than vanilla, and original mod)
• less buggy handling of attachments in general
• a 'clear' button for the 'send' tab
• new 'enhanced' item overlay mode. colorful! Also now has a higher contrast version and color override mode, with a helpful color picker and some preview squares! Left squares are for the colors without override mode, right squares are for the colors with it on. If a text field isnt filled the color component is inherited, based off whether enhanced and high contrast are on.

known issues:

• error that happens when sending mail / taking all, without sufficient room. difficult to fix, is harmless. if you get a message about an overflow container, clear up your inventory and go place an item in a dimension.
• the overlay is missing/misaligned the first time it is loaded. this is due to incorrect values reported by the game's native code when a UI frame is first created. there is no way to correct this, so just reopen your bags.
• sometimes the native UI reports all zeroes for every value. only fix is to reopen bags. a helpful warning message will show in place of the attachment list when this happens.