Read from the error pipe in a separate thread

If the build process tries to write more bytes than will fit in the pipe
buffer, it will block until the parent process does a read. However, the
parent process will only do a read after the child process has exited or
died, leading to a deadlock. Fix this by doing the read in a separate
thread.
Add a devel version for Tesseract 3.03
Remove trailing whitespace.
Instruct homebrew to use cxx11 lib for building tesseract devel.
More trailing whitespace.
tesseract: update 3.02.02_2 bottle.