* match search buffer against scrollback content
* adjust view to ensure matched content is visible
* create selection on a successful match
* finalize selection when user presses enter (to "commit" the search)
* ctrl+r searches for the next match. Needs more work though.
This adds a new state, 'is_searching'. While active, input is
re-directed, and stored in a search buffer. In the future, we'll use
this buffer and search for its content in the scrollback buffer, and
move the view and create a selection on matches.
When rendering in 'is_searching', everything is dimmed. In the future,
we'll render the current search buffer on-top of the dimmed "regular"
terminal output.
The CLEAR action is so common, that explicitly clearing the entire
params array, which is kind of big, is too slow.
Clear it lazily instead. Meaning, we only set 'idx' (count) to 0 in
CLEAR. Then whenever we parse a parameter, clear the value and sub
parameters.
With this assumption, we can replace 'a % b' with 'a & (b - 1)'. In
terms of instructions, this means a fast 'and' instead of a slow
'div'.
Further optimize scrolling by:
* not double-initializing empty rows. Previously, grid_row_alloc()
called calloc(), which was then followed by a memset() when
scrolling. This is of course unnecessary.
* Don't loop the entire set of visible rows (this was done to ensure
all visible rows had been allocated, and to prefetch the cell
contents).
This isn't necessary; only newly pulled in rows can be NULL. For
now, don't prefetch at all.
That is, remove the 'regular' and 'bright' color arrays. This is
possible since the 256-color array is defined such that the first 16
colors map to the regular and bright colors.
This implements OSC 4, 10, 11 - change <color>/foreground/background,
and their corresponding 'query' variant (which was already implemented
for OSC 10/11).
It also implements OSC 104, 110, 111 - reset
<color>/foreground/background.
Set corresponding terminfo entries to signal this support to clients.
