Make BarGraph example graph icon configurable

Set 'wtf.mods.bargraph.graphIcon` to the string you want to use as the
graph icon.

_sample_configs/bargraph_config.yml

@@ -10,18 +10,12 @@ wtf:
   refreshInterval: 1
   mods:
     bargraph:
-      colors:
-        from:
-          name: coral
-          displayName: grey
-        to:
-          name: white
-          price: green
       enabled: true
+      graphIcon: "🍎"
       position:
         top: 2
         left: 0
         height: 2
         width: 2
       refreshInterval: 30
-      updateInterval: 15
+      updateInterval: 15

_sample_configs/complex_config.yml

@@ -80,10 +80,6 @@ wtf:
       secretFile: "~/.config/wtf/gcal/client_secret.json"
       withLocation: true
     gspreadsheets:
-      enabled: true
-      secretFile: "~/.config/wtf/gspreadsheets/client_secret.json"
-      refreshInterval: "300"
-      sheetId: "id_of_google_spreadsheet"
       colors:
         values: "green"
       cells:
@@ -93,11 +89,15 @@ wtf:
         addresses:
         - "A1"
         - "A2"
+      enabled: true
       position:
         top: 0
         left: 0
         width: 1
         height: 1
+      refreshInterval: "300"
+      secretFile: "~/.config/wtf/gspreadsheets/client_secret.json"
+      sheetId: "id_of_google_spreadsheet"
     git:
       commitCount: 5
       enabled: true

bargraph/widget.go

@@ -50,7 +50,8 @@ func MakeGraph(widget *Widget) {
 
 	}
 
-	widget.BarGraph.BuildBars(20, "🌟", stats[:])
+	icon := wtf.Config.UString("wtf.mods.bargraph.graphIcon", "✭ ")
+	widget.BarGraph.BuildBars(20, icon, stats[:])
 
 }