Replace compile-on-save with perform-on-save.

Can be either nil (no action), or a string naming the sbt action to perform when a file is saved. Defaults to "compile" (although I prefer "test-quick").
Merge pull request #21 from sellout/perform-on-save

Replace compile-on-save with perform-on-save.
prep for https://github.com/ensime/ensime-server/issues/527
Merge pull request #22 from fommil/prep_527

prep for server loading config on startup
active module name passed to server to support refactoring
Merge pull request #23 from fommil/more_prep_527

active module name passed to server to support refactoring
Merge remote-tracking branch 'refs/remotes/upstream/master'

Conflicts:
	ensime-mode.el