Add support for lein's `:managed-dependencies` (#506)
Add support for lein's `:managed-dependencies` (#506)

Prior to this commit, figwheel would error out on any projects
that were using lein's `:managed-dependencies` feature to
inject version numbers into the project.  This commit makes sure
that `:managed-dependencies` is one of the included keys selected
from the original project map, and allows projects that use this
key to run properly.
bhauman/lein-figwheel,verma/lein-figwheel,bhauman/lein-figwheel,bhauman/lein-figwheel,verma/lein-figwheel