nanobeep - ZX Spectrum beeper music engine
by utz 09'2015 - 04'2016
1tracker version by Shiru 01'2018


utz's take on extremely compact music engine, even more so than the 
100-byte Huby engine. The original code is just 56..77 bytes large 
depending of feature set. It is modified to be used in 1tracker, so it 
is a bit larger, but the data format is mostly the same, so you can use 
original player, if you need to (just delete loop pointer at the 
beginning). 

The engine features two channels of tone, single click drum. Global 
speed only. The drawback of such tiny design is very strong detune, 
especially of the lower octaves, so it is normal that most of notes is 
way out of pitch. 


The columns are:

T1 d T2 d C
.... .... .
|  | |  |
+ch1 +ch2

T1,T2 : Note, C-0..B-7 (but out of tune a lot)
    d : Detune, 1..9
	C : Click drum, empty or 1
