Allow user to move caret to end of a line or its beginning

On Windows the user can press the 'home' or 'end' key to jump around. On
OSX he has to use cmd+arrow keys to move around.

If the user holds down shift while performing the above operations the
whole line will be selected from where the caret was currently placed.

luigi/widget/text.lua

@@ -91,6 +91,12 @@ local function moveCaretLeft (self, alterRange)
     selectRange(self, not alterRange and index, index)
 end
 
+-- move the caret to the beginning of the line
+local function jumpCaretLeft (self, alterRange)
+    trimRange(self)
+    selectRange(self, not alterRange and 0, 0)
+end
+
 -- move the caret one character to the right
 local function moveCaretRight (self, alterRange)
     trimRange(self)
@@ -104,6 +110,13 @@ local function moveCaretRight (self, alterRange)
     selectRange(self, not alterRange and index, index)
 end
 
+-- move the caret to the end of the line
+local function jumpCaretRight (self, alterRange)
+    trimRange(self)
+    local text = self.value
+    selectRange(self, not alterRange and #text, #text)
+end
+
 local function getRange (self)
     trimRange(self)
     if self.startIndex <= self.endIndex then
@@ -269,11 +282,27 @@ This color is used to indicate the selected range of text.
 
         elseif event.key == 'left' then
 
-            moveCaretLeft(self, Backend.isKeyDown('lshift', 'rshift'))
+            if Backend.isKeyDown('lgui', 'rgui') then
+                jumpCaretLeft(self, Backend.isKeyDown('lshift', 'rshift'))
+            else
+                moveCaretLeft(self, Backend.isKeyDown('lshift', 'rshift'))
+            end
 
         elseif event.key == 'right' then
 
-            moveCaretRight(self, Backend.isKeyDown('lshift', 'rshift'))
+            if Backend.isKeyDown('lgui', 'rgui') then
+                jumpCaretRight(self, Backend.isKeyDown('lshift', 'rshift'))
+            else
+                moveCaretRight(self, Backend.isKeyDown('lshift', 'rshift'))
+            end
+
+        elseif event.key == 'home' then
+
+            jumpCaretLeft(self, Backend.isKeyDown('lshift', 'rshift'))
+
+        elseif event.key == 'end' then
+
+            jumpCaretRight(self, Backend.isKeyDown('lshift', 'rshift'))
 
         elseif event.key == 'x' and Backend.isKeyDown('lctrl', 'rctrl', 'lgui', 'rgui') then