more fixes for my modded speakup

[David]

Multi line reads like say screen now release the lock between lines
so the voice thread can get in earlier.
smarter highlight tracking scores colors to determine what should be read.
a bunch more work so synths can write usb devices etc.
This is a work in progress.
moved bleep into the main with a timer so the catch-up thread only
handles the synth. then for soft synth, we won't even create it.
The buffer.c code now allows gets of strings which auto-lock
until the next status check so we will be able to write blocks
of data to a system device driver.
Soon I can use my dec talk on a netbook with a usb to serial converter!
Hopefully I didn't break anything. I only have a dectalk for testing.