Without a parameter, it clears all buffers. A numeric parameter will
clear only a specific buffer: 1 = INKEY$ buffer (and other traditional
QB input commands), 2 = _KEYHIT buffer, 3 = INP(&H60) buffer. The last
one is not actually cleared, but we pretend we've read all the data from
it.
To ensure no stray characters, use this command immediately before the
code you wish to sanitise. You never know when the user might bang on
the keyboard, and this also helps to avoid stray key release values
persisting in the _KEYHIT buffer.
Added new _STRCMP and _STRICMP commands for quick string comparisons.
Cleaned up QB64 to finish removing the QUI (quick user insert) code and folders.
Altered UCASE and LCASE routines to be faster in some situations for us.
