add categories to item types
Fix recipe iv_mutagen_troglobite
Fix craft depenedent of light
Fix recipe iv_mutagen_trogLOBITE
rebalance light dependence
IV mutagen insertion

These add IV mutagens to the Lab chem rooms; each is comparatively rare
but the amount of them should make the odds of one or two reasonable.  I
intentionally made Fish more common because there's no renewable way to
make it, IIRC: you need canned goods.

Also makes flavored mutagens recipe-locked (so, major Nerf) and includes
recipe books for all of them, which tend to spawn in relevant lab rooms.
But if you find one on a scicorpse, that's not a bug.  Check the item
ID.  :-)

Finally, adds lab notes to the computers to keep the backstory-support
going.
quotes v. semicolon

Fixed typo.
Added border and header to input context help
fix-string-overlapping-in-ranged-help
header renamed + comment fix
adv inv fix
ident fix
fix memleak in input_context::display_help()
add ESC key to exit from search result
try-to-fix-help-displaying
null checking gone wild
remove comment
adv inv: tweak show popup
prevent accessing invalid monster instances
use a dedicated item_category class