?tile command: search on display name

[HeladoDeBrownie]

most players aren't going to be familiar with the internal ids of creatures, so it makes sense to let them input a display name, e.g., ?tile sheba.

some considerations:

• some display names are ambiguous. but, some ambiguous display names have a tile that's unambiguous. in those cases, it makes sense to display that tile despite the ambiguity. dromad traders come to mind.
• some display names map to the same internal id, but have a consistent tile and coloration per display name. stat saps come to mind.
• while we could have a separate command that gives the id from the display name, this not only creates an extra step and channel noise, but loses information (see last point).

[syntaxaire]

This was implemented with b2ad5d0.