Merge gaps support as-is

This code was copied over unmodified from https://github.com/Airblader/i3-gaps.

I have split out the differences between i3-gaps and i3 into three areas:
1. Gaps
2. i3bar height
3. rgba colors

parser-specs/commands.spec

@@ -43,6 +43,7 @@ state INITIAL:
   'title_window_icon' -> TITLE_WINDOW_ICON
   'mode' -> MODE
   'bar' -> BAR
+  'gaps' -> GAPS
 
 state CRITERIA:
   ctype = 'class'       -> CRITERION
@@ -95,6 +96,23 @@ state BORDER:
   '1pixel'
     -> call cmd_border("pixel", 1)
 
+# gaps inner|outer|horizontal|vertical|top|right|bottom|left [current] [set|plus|minus|toggle] <px>
+state GAPS:
+  type = 'inner', 'outer', 'horizontal', 'vertical', 'top', 'right', 'bottom', 'left'
+      -> GAPS_WITH_TYPE
+
+state GAPS_WITH_TYPE:
+  scope = 'current', 'all'
+      -> GAPS_WITH_SCOPE
+
+state GAPS_WITH_SCOPE:
+  mode = 'plus', 'minus', 'set', 'toggle'
+      -> GAPS_WITH_MODE
+
+state GAPS_WITH_MODE:
+  value = word
+      -> call cmd_gaps($type, $scope, $mode, $value)
+
 state BORDER_WIDTH:
   end
     -> call cmd_border($border_style, -1)

parser-specs/config.spec

@@ -25,6 +25,9 @@ state INITIAL:
   'bar'                                    -> BARBRACE
   'font'                                   -> FONT
   'mode'                                   -> MODENAME
+  'gaps'                                   -> GAPS
+  'smart_borders'                          -> SMART_BORDERS
+  'smart_gaps'                             -> SMART_GAPS
   'floating_minimum_size'                  -> FLOATING_MINIMUM_SIZE_WIDTH
   'floating_maximum_size'                  -> FLOATING_MAXIMUM_SIZE_WIDTH
   'floating_modifier'                      -> FLOATING_MODIFIER
@@ -65,6 +68,32 @@ state IGNORE_LINE:
   line
       -> INITIAL
 
+# gaps inner|outer|horizontal|vertical|top|right|bottom|left <px>
+state GAPS:
+  scope = 'inner', 'outer', 'horizontal', 'vertical', 'top', 'right', 'bottom', 'left'
+      -> GAPS_WITH_SCOPE
+
+state GAPS_WITH_SCOPE:
+  value = number
+      -> call cfg_gaps($workspace, $scope, &value)
+
+# smart_borders true|false
+# smart_borders no_gaps
+state SMART_BORDERS:
+  enabled = '1', 'yes', 'true', 'on', 'enable', 'active'
+      -> call cfg_smart_borders($enabled)
+  enabled = 'no_gaps'
+      -> call cfg_smart_borders($enabled)
+
+# smart_gaps on|off
+state SMART_GAPS:
+  enabled = '1', 'yes', 'true', 'on', 'enable', 'active'
+      -> call cfg_smart_gaps($enabled)
+  enabled = '0', 'no', 'false', 'off', 'disable', 'inactive'
+      -> call cfg_smart_gaps($enabled)
+  enabled = 'inverse_outer'
+      -> call cfg_smart_gaps($enabled)
+
 # include <pattern>
 state INCLUDE:
   pattern = string
@@ -135,10 +164,10 @@ state DEFAULT_BORDER_PIXELS_PX:
   end
       -> call cfg_default_border($windowtype, $border, &width)
 
-# hide_edge_borders <none|vertical|horizontal|both|smart>
+# hide_edge_borders <none|vertical|horizontal|both|smart|no_gaps>
 # also hide_edge_borders <bool> for compatibility
 state HIDE_EDGE_BORDERS:
-  hide_borders = 'none', 'vertical', 'horizontal', 'both', 'smart'
+  hide_borders = 'none', 'vertical', 'horizontal', 'both', 'smart_no_gaps', 'smart'
       -> call cfg_hide_edge_borders($hide_borders)
   hide_borders = '1', 'yes', 'true', 'on', 'enable', 'active'
       -> call cfg_hide_edge_borders($hide_borders)
@@ -297,13 +326,16 @@ state FOCUS_ON_WINDOW_ACTIVATION:
       -> call cfg_focus_on_window_activation($mode)
 
 # workspace <workspace> output <output>
+# workspace <workspace> gaps inner|outer <px>
 state WORKSPACE:
   workspace = word
-    -> WORKSPACE_OUTPUT
+    -> WORKSPACE_COMMAND
 
-state WORKSPACE_OUTPUT:
+state WORKSPACE_COMMAND:
   'output'
       -> WORKSPACE_OUTPUT_WORD
+  'gaps'
+      -> GAPS
 
 state WORKSPACE_OUTPUT_WORD:
   output = word