- hot spots are clickable screen areas (e.g. in menus and prompts) that   generate key-strokes
- commands may be from 1 to 127 ASCII-characters in length
- currently using the X10 mouse reporting mode, may change
- all mnemonics strings (~Example) are automatically hot-spots
- The new ~ @-code defines a hot spot
- Any screen-clear operation clears all hot spots
- sbbs now tracks the current screen (cursor position) row
- eliminated the old "tos" (top-of-screen) boolean (row == 0 indicates "tos")
- created an sbbs_t::ungetstr() method
- keep track if in pause (hit a key) prompt, for special mouse behavior

new JS console object:
- row property
- tos property is now read-only (and deprecated)
- new methods:
  add_hotspot()
  clear_hotspots()
  scroll_hotspots()

redrwstr() gets some UTF8 touch-ups as part of this commit. <shrug>