v0.7.1: the keyboard, finished frames, Minecraft and Smash

Fixes from the GBAtemp reports, and more games.

The on-screen keyboard works again. With Switch Frame Tap installed, the software keyboard crashed when it opened - in homebrew apps (thanks kingboxnt) and in some retail games too (Minecraft). The module was using up a small system budget that all applets share (6 IPC sessions), so the keyboard applet had none left. It now gets its sessions through the system's service manager instead.

No more corrupted frames in fades and menus (thanks SooraMaru). Some games (Pokemon Sword/Shield) hand a frame over well before the GPU has finished drawing it, and the capture sometimes gave up waiting and took a half-drawn picture - the dotted frames in fades and menu transitions. It now waits for the frame to be finished, and re-takes a frame if the game started drawing into it again while it was being copied.

Games that keep each frame in its own buffer now stream: Minecraft and Super Smash Bros. Ultimate showed a mix of several screens, or no picture. The module now finds those buffers by watching which one changes with each frame (a few seconds after the game starts, and again when a game makes new ones - Minecraft loading a world).

Steadier streams:

• A busy video engine (another app recording, or the system scaling a game in ReverseNX's docked mode) no longer ends the stream for the whole boot; it carries on or restarts by itself.
• A docked game's black menu transitions no longer make the stream zoom into the 720p corner for a few seconds.
• A rare startup case where no game would stream until a reboot is fixed.

Updating: unzip switch-frame-tap-0.7.1-switch.zip over the SD card root and reboot (settings and screenshots are kept). The viewers did not change; the 0.7.1 viewer zips are the same program.