[PATCH] Tribute enhancements

[alpha123]

A collection of miscellaneous small improvements to tributing.

tribute-notifications.patch: notifies the receiver of a tribute, "alpha123 has sent you 1000 food."

tribute-insufficient-resources.patch: notifies the sender of a tribute if they have insufficient resources. Actually, this patch is so trivial it removes more code than it adds. :P

tribute-shift-click.patch: allows for tributing to function a bit like unit training. Shift-click will tribute 500, shift-click-click will tribute 1000, etc. Also changes the tooltip for the tribute resource icons to be more informative, "Tribute 100 food to alpha123. Shift-click to tribute 500."

None of these patches depend on each other, so apply as many as you like.

All the patches should be applied from binaries/data/mods/public/.

[leper]

In 13176:

Notify the player on receiving a tribute. Patch by alpha123. Refs #1839.

[leper]

Insuffient resources patch:
I do remember why I didn't use TrySubtractResources(): It adds the resources to the used ones (which I'm not really sure if it should do this for tributes). I think we should factor out the message code (the if actually) and just pass GetNeededResources(amounts) to this new function (or just call it in there).

Shift click patch:
I'd add another hotkey for batch tributing. Do we need both tributeResource and flushTributing?

[alpha123]

Someone remind me to think before editing patches manually next time.

[leper]

In 13201:

Add shift-clicking to tribute multiples of 500. Patch by alpha123. Refs #1839.

[alpha123]

Refactored to not use TrySubtractResources.

[leper]

In 13276:

Add notification for missing resources when tributing. Patch by alpha123. Fixes #1839.

[leper]

Thanks for the patch.

[elexis]

In 23065:

Refactor diplomacy dialog to use object orientation paradigm using the class keyword, refs #5387.

Includes dilomacy colors, tribute buttons, spy request buttons, attack request buttons, minimap panel, idle worker button, ceasefire counter.
Differential Revision: ​https://code.wildfiregames.com/D2365

Use hotkey release event from rP19028 to remove input.js state and evil global nested closure hackery from rP13201, refs #1839, #3194.
Fixes masstribute selecitonchange issue subject of D1191.