This expands support for 24-bit color for terminals that support the
ISO 8613-6:1994 escape sequences (same as xterm), allowing this support
to be enabled by setting % COLORTERM to "truecolor" (or 24bit or 24-bit),
or by setting TCELL_TRUECOLOR to "on", or by setting $TERM a value that
ends in the word "-truecolor".
As this is handled by the runtime now, we no longer need to create magical
database entries for -truecolor options.
A colors.go demo is provided to show off 24-bit color support.
This changes the database to use sha1 based file names. Its not
beautiful, but this is the BS we have to do to cope with the garbage
that is case insensitive filesystems.
Legacy databases are still honored, if you have them.
This completely restructures the database of terminal types, putting
each terminal in its own file. We also compress the database files,
and use infocmp instead of trying to use the C level API.
The mkdatabase script will rebuild the entire database from the terminfo
files on the system. Individual entries can also be built by simply running
the mkinfo program with the terminal type.
