Counter expressions

[basicer]

Short roundup of the initial problem

• You cant get the middle click menu for counters with a track pad
• Math is hard.

What will change with this Pull Request?

• Shift+Clicking a counter will show the middle click menu.
• When setting a counter value, you can type a math expression in the box and the counter will be set to the result.

[skwerlman]

Is it possible to reference the current value of the counter?

[basicer]

Yup, the current value is x.

[ebbit1q]

Err? Why can't you middle mouse button on trackpad? isn't it triple tap everywhere? I can do this just fine.....

[ctrlaltca]

Works as expected. 👍

A few notes:

• I was in doubt about the maintainability of including en external library, but it seems like it compiles fine cross-os, and the inclusion of MIT licensed code in a GPL project is ok; the original code seems to be https://github.com/yhirose/cpp-peglib
• as a c64 guy the first expression I tried was x/0, and the result was -MAX_INT. Is the result expected to be 0, since it should be treated as an error?
• I'm not sure how needed trigonometric and other functions are, but since they are for free, they are fine.

[ctrlaltca]

Err? Why can't you middle mouse button on trackpad? isn't it triple tap everywhere? I can do this just fine.....

On macs the "three finger tap" is tied to a useless "lookup" function. The shift+click addition can be quite useful there.

[tooomm]

Do we want to let the user know that he can do calculations?
There is no exposure of this feature in the interface yet, right?

[basicer]

I suppose we could put it in the tips and tricks dialog.

[tooomm]

Haven't thought about that one :)

That would go here:
https://github.com/Cockatrice/Cockatrice/tree/master/cockatrice/resources/tips

Do you want to include that in this PR as well?

[ZeldaZach]

Should be included in the PR since it's such a big change. Re: tom's comment on new tip dialog

[ctrlaltca]

Added tip entry; also, fixed tip-of-the-day dialog image size calculation.