Add draft entry so solvers can mark tentative letters

[ianfhunter]

In the solving mode of Crosshare, add a "Draft" mode, enabled with "." to give a visually different entry so that one can track answers that are "locked in" or ones that are unconfident.

As described in #414 , the behaviour is the same if all cells are filled out, versus non-draft cells - it will bring up the end screen/incomplete screen.

Basic appearance:

Interaction with hilights:

Also works fine with rebuses.

Closes #414

[mdirolf]

Screenshots look great, as does the code from the quick glace I gave it. Will try to give a thorough review or merge tomorrow. Thank you!

[mdirolf]

I'm not sure this is worth any time to fix but one minor issue I noticed is that the color of the rebus text while it's being edited is based on the current draft status of that particular cell, not the current draft setting. Once the rebus is saved it seems to behave as expected.

I.e. go into draft mode and put a single letter in a cell. Exit draft mode and go back to that cell and start to enter a rebus - the color of the text as you're editing it will be the draft color.

[mdirolf]

Looks good - I made a note about the color of rebus entries but that's the only thing I saw that could use improvement. LMK if you feel like taking a look at that - otherwise I think I'm OK with merging this as-is.

[ianfhunter]

Looks good - I made a note about the color of rebus entries but that's the only thing I saw that could use improvement. LMK if you feel like taking a look at that - otherwise I think I'm OK with merging this as-is.

I think I fixed the rebus now. Subtle one - thanks for catching

[mdirolf]

Looks good - going to merge. Thanks again!