as a temporary workaround for the fact that SerialUSB is often blocking,
this crude implementation makes the low-level C usbSendBytes function
non-blocking (with a return code of bytes sent) and implements a 2ms
timeout in the wirish write() function.
also adds begin(), end(), getDTR(), getRTS(), pending(). device is still
initialized the old fashioned way during init() so that, eg, autoreset
will work. includes a simple multi-test program.
Commit 70a18f96b6 forces init() to be
called before any statically allocated object constructors for the IDE.
This adds the change to the examples for users not using the IDE.
Relicensed the bulk of libmaple under the more permissive MIT License,
from GPLv3. Files that were largely or entirely derived from
the Arduino, STM, or Lanchon retain their original licenses.
