Reorganize cucumber features

features/actions/quit.feature

@@ -1,6 +0,0 @@
-Feature: quit action
-
-  Scenario: quits on alt+q keys press
-    Given uhwm is running
-    When I press the alt+q keys
-    Then uhwm should terminate successfully

features/session/termination.feature

@@ -0,0 +1,6 @@
+Feature: program termination
+
+  Scenario: terminates when requested to quit
+    Given uhwm is running
+    When I tell uhwm to quit
+    Then uhwm should terminate successfully

features/steps/run_steps.rb

@@ -19,6 +19,10 @@ When /^I run uhwm with options? (-.+)$/ do |options|
   uhwm_run options
 end
 
+When /^I tell uhwm to quit$/ do
+  x_key 'alt+q'
+end
+
 Then /^the exit status must be (\d+)$/ do |exit_status|
   assert_exit_status exit_status.to_i
 end