Adapt menucolors

[tung]

Menucolors allows players to set the color and formatting of menu entries according to textual patterns, expressed with regexps or NetHack's globbing syntax. Challenges/thoughts:

• Regexps require external library support, making it that much harder to work on Windows or constrained platforms.
• NitroHack distinguishes normal menus from object menus; the latter includes object appearance, BUCness (if available), weight (if available) and a flag stating whether the object is equipped or in use. Will a single regexp be enough, or will more sophisticated rules be needed?
• What about the accelerator? How will multi-field menus be handled?
• NitroHack already does some coloring for object menus based on BUCness and whether it's equipped or in use. How will that interact with menucolors? Can/should they be expressed as default menucolors settings instead?
• Menucolors for object menus expresses game knowledge that differs between players. However, menucolors for most text-based menus is because NetHack does a poor job coloring them itself, e.g. coloring skills based on level or spells based on failure rate. Should menucolors cater to non-object menus? Excluding it somewhat simplfies the menucolors options UI, but may exclude legitimate use cases, e.g. coloring finger of death in the spell menu.
• Are there any ways to ease migration of existing menucolors settings blocks? What about players who share or want to borrow other people's settings?
• Sometimes, the purpose of menucolors lines aren't immediately obvious, so should it support something like comments?
• A menu test pattern would be really useful for testing the rules without having to have a game live. Is such a thing possible?