Update to latest stevedore
Add pallet.script.lib/file like c.java.io/file

Adds a file function for concatenating path elements in script.
Add debconf-set-selections action

The action can be used to set debconf selection values.  It runs before any
`package` action.
Add :preseeds option to :packages install strategy

The :preseeds key takes a sequence of debconf-set-selections maps.
Add exclusion to prevent Enlive from checking every Clojure version.
Remove outdated launch script generator
Remove some reflection warnings
Remove unused cache implementation
More reflection warnings
Remove unused get-session function
Update script-exec, pallet-common and fsmop
Remove reflection warnings