device.hardware: don't request RAM writes of >4096 bytes.

applet.yamaha_opl: unbreak handling of VGMs for a different chip.

protocol.vgm: fix off-by-1 in 0x7X opcodes.

protocol.vgm: fix parsing of variable length header.

applet.yamaha_opl: accumulate fractional sample delays. This is done to correct for write latency, since some OPx clients, such as VGM, assume that writes take zero time. This also cleans up the handling of clocking all around, to make it easier to generalize to other Yamaha chips.

applet.yamaha_opl: detect dual/special OPL2 in VGM.

applet.yamaha_opl: web: fix a glitch at the end of playback.

applet.yamaha_opl: reset feature level with registers.

applet.yamaha_opl: restructured documentation. NFC.

applet.yamaha_opl: sanity check features used by OPL client.