Rune - Syscall work, stabilization

Rune - Syscall work, stabilization

* Fix bug in threadSleep*() where ms == 0 was not doing an indefinite
  sleep.  Mainly for WCHAN sleeping.

* Fix bug in EmitRAS_SemanticEnter() where LVALUE scope was being ignored,
  causing the zeroing code to overflow the type.

* Fix bug in GenAllocReturnBase() where the data storage status was not
  being properly set, resulting in a lock count mismatch.

* Remove some debugging, convert other debugging from stdout to stderr.

* Add a bunch of fd-related system calls.  Also change ('fix') the default
  behavior for read() and write() to use non-blocking I/O, loop internally
  if necessary, and also handle EINTR restarts.

* Greatly simplify the Syscall structure.  We no longer use sc_RetType
  or sc_Args so get rid of them.

* Remove File.fgets(), add File.fgetln().  Also add File.fgetbuf()
  which is similar to fgetln() in avoiding copies, but operates on
  the whole buffer when possible instead of line-by-line.

* Fix fread(), fwrite(), and related stdio functions to work properly
  with non-blocking I/O and EINTR.