scr_printf: implement color management via custom escape code

[israpps]

this PR makes scr_printf coloring simpler, via a custom escape sequence

this is a hybrid between actual ansi escapes, and windows color command from cmd.exe just to keep impl small and the sequence as small as posible

there are 16 default colors (that the program can customize)

the sequence is \x1b followed by two hex chars

to avoid C compiler messing up, its better to use the octal version of the escape

as an example:

scr_printf("hello people \03304 This is red text! \0330F Now back to white!\n");

[uyjulian]

Lgtm