Being able to interact with the python context in the Bitbake task execution
environment has long been desireable. This patch introduces such a
mechanism. Executing "bitbake X -c devpyshell" will open a terminal connected
to a python interactive interpretor in the task context so for example you can
run commands like "d.getVar('WORKDIR')"
This version now includes readline support for command history and various other
bug fixes such as exiting cleanly compared to previous versions.
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
