Caching improvements & no trampoline on windows
Daniel Compton did some great work solving the caching issues.
There is also a very confusing problem with lein trampoline on Windows
see issue #682. So I turned off the auto-trampoline feature for
Windows which allowed the for the elegent use of Rebel readline by
just calling lein figwheel.
Windows users can still elect to use trampoline with figwheel and get
the benefits of rebel-readline but the will have to call lein
trampoline figwheel and this should be done with the knowledge that
they may experience a classpath corruption issue.