#424 Add item ctrl-rightclick and shift-rightclick functionality

[Saiapatsu]

Allows using shift-rightclick to apply an item and control-rightclick to mark an item.

This is in response to someone in rock808's server who was taught to shift-rightclick to apply an item (like in jxclient?) by in-game magic mouths, and dropped a godgiven starter item.

It also makes the middle mouse button redundant, allowing one to apply and mark items without it.

0001 implements all of the above
0002 turns the if/elses into an overkill switch statement

[rock808]

Just tried it. Works great! thanks!

[Kevin Zheng]

Committed patch 1, thanks. Patch 2 pending.

[Kevin Zheng]

I think patch 2 makes it a bit more confusing to understand what is going on. Let's wait to make this change until these combinations actually do something different.