rename actions, allow specifying branch in params

update -> update_all, update_default -> update

new update action takes *branch* param and works with it, if
you additionally provide *revision* param, that revision will
be checked out into *branch* work-dir.

cleanup spec, to be continued...
separate contexts
drop che chdirs
mimic correct functionality in rspec, clone into both agent dir and dir/puppet.git
more spec goodness
replace chdir with cd
use env_dir
use env/git_dir again
don't create new repo for each test
cleanup some vars
let agent be @agent
add few helper methods to spec
more spec cleanups
add branch param to ddl file
accept branch param in application/puppetupdate.rb