enable mouse events in the demo. spawn a thread from main() which
brokers all input events. it will consume mouse events, and
publish keyboard events to a queue. rewrite all demo notcurses_getc()
calls to demo_getc() equivalents.
Allow -1 in move specification to remain where we are on that
axis (#210), necessary for context-sensitive aligned output.
Add _aligned forms to printf and vprintf. Invert various output
functions so that simpler form is static inline wrapper around
more complicated form, rather than complicated form being a
static inline composition, facilitating atomic move+output. All
output forms now have a simple form (no alignment, placement at
cursor), an _aligned() form, and a _yx() form.
Request and parse up mouse messages. We handle up to 11 mouse
buttons, 3 modifiers (currently thrown away), motion while
holding down a button, and loss/gain of focus. I've added twelve
new NCKEYs: one for each button, and one for release. In addition,
I've introduced the 'ncinput' struct, which encodes the nckey plus
extra data. The only extra data thus far is coordinates for mouse
events. It is not necessary to provide a ncinput to all input
functions; NULL can be provided if the caller doesn't care about
details. All demos are updated. notcurses-input has been updated
to decode full information of returned ncinputs.
The primary resource for this work was Dickey at al's "XTerm Control
Sequences", https://invisible-island.net/xterm/ctlseqs/ctlseqs.html.
