More notes.
Reset code is in another file. Reset calls main.
Code aesthetics.
Calling conventions written up.

This note will be modified if, after putting in it application, it appears
that some parts of it don't make sense.
Better structure of the code.
Modified reset procedure

Rendering is disabled early on (famicom). Clear v-blank bit if set before
waiting for v-blank.
New routine wait_vblank_setctrl

This routine just wait vblank and set $2000 with accumulator value.