scripts: Fix duplicate install error message
scripts: Add modules update method
scripts: Display usage for unsupported commands
Ignore emacs buffers
Ignore Emacs buffers

Also add zotonic-setup and zotonic-teardown to bin/zmm as done in
bin/zotonic. Minor fixes to zotonic-modules and HTTP args printed in
service_base_modules for debugging purposes.
scripts: Remove all module-related HTTP service calls

The HTTP service calls for activating, deactivating, and restarting
modules are now handled by a call to the Zotonic Erlang node via
$ERL_CALL.