basic_tips_tricks: Improve for-next-goto tip description.
msx_io_ports: Add SoundStar ports.
resources: Add Philips SAA1099 application manual.

Used by the SuperSoniqs SoundStar sound expansion.
getslot: Document the output value of ID bits 4-6 more explicitly.
getslot: Early return when the slot is not expanded.

This also keeps the secondary slot bits zero when it is not expanded. Although
non-zero bits are fine in terms of having a valid ID, since for unexpanded slots
these bits are irrelevant, this makes sure the slot ID is a normalized value.
low-level-disk: New “Low-level disk storage” article by Wouter Vermaelen.
hbi55: Update text and sample program to better reflect hardware.

* Tweaks block diagram based on service manual.
* Document port B bits 4-5.
* Correct the read & write procedure.
* Fix example so that it turns off chip enable after reading / writing.
* Add short circuit warning.
vdp_guide: Test program for r#18 interaction with copy commands and the display.

This test program cycles through four different stages:

1. Full screen copy while r#18 horizontal offset decrements, sprites enabled.
2. Full screen copy while r#18 horizontal offset increments, sprites enabled.
3. Full screen copy while r#18 horizontal offset decrements, sprites disabled.
4. Full screen copy while r#18 horizontal offset increments, sprites disabled.
vdp_guide: Changing r#18 with sprites disabled blanks in either direction.

Confirmed by test program.
vdp_guide: Changing r#18 during VDP command also corrupts with sprites enabled.

Confirmed by Artrag and PingPong. See:
split_guide: Fix link to split tests.
vdp_tut: Remove unnecessary nops.
yjk: Select screen 10-12 via CHGMOD mode 8 and the YJK/YAE bits in r#25.

Oddly, the MSX2+ / turboR BIOSes do not support screen modes above 8.
Confirmed in the BIOS disassembled source code.
resources: Add link to Arjen Zeilemaker’s disassembled BIOS source files.
resources: Add MSX BIOS The Complete MSX BASIC I/O Listing.

Based on HansO’s scans, parts 1 & 2 combined with rotated pages.
msx_io_ports: Add turbo available bit to Panasonic expanded I/O port.

Based on openMSX information and implementation;

Sanyo MSX2+ machines provide the Panasonic expanded I/O port but do not support
the turbo 5.37 MHz CPU mode. This is indicated by bit 2.
yjk: Remove incorrect and unnecessary id.
vdp_detection: Elaborate a bit more.
z80instr: Clarify that the M1 wait is not specific to the MSX-ENGINE.
z80: Update from manual revision 05 (2005-02) to revision 11 (2016-08).