Preliminary ability to use Jinja2 {{ }} to replace ${foo.bar} in playbooks.  Can't use both at the same time per line.

as it is /bin/false on many systems but /usr/bin/false on OS X
test/playbook1.yml now just does command true, rather than command /bin/true,
again so that it works on OS X

Changed from using which false to just using command false to
make it simpler and also match how playbook1.yml works

refactoring of playbooks now warranted, which we'll do before we move on.   This variable assignment
system makes nearly all possible magic possible, for we can use these variables however we like,
even as module names!

(Using varReplace function originally from yum, thanks Seth)

Playbook test upgrades, made some notes about callbacks we need to add.  Still need to compare events
recieved vs expected so we can be notified if this test breaks, and also to add some more detailed
playbooks that use includes & async, etc.