Add columnCount var to Editor::moveLeft and Cursor::moveLeft

spec/editor-spec.coffee

@@ -333,12 +333,22 @@ describe "Editor", ->
             editor.moveLeft()
             expect(editor.getCursorScreenPosition()).toEqual(row: 0, column: buffer.lineForRow(0).length)
 
+          it "moves the cursor by n columns to the left", ->
+            editor.setCursorScreenPosition([1, 0])
+            editor.moveLeft(4)
+            expect(editor.getCursorScreenPosition()).toEqual [0, 26]
+
         describe "when the cursor is on the first line", ->
           it "remains in the same position (0,0)", ->
             editor.setCursorScreenPosition(row: 0, column: 0)
             editor.moveLeft()
             expect(editor.getCursorScreenPosition()).toEqual(row: 0, column: 0)
 
+          it "moves the cursor by n columns to the left", ->
+            editor.setCursorScreenPosition([0, 0])
+            editor.moveLeft(4)
+            expect(editor.getCursorScreenPosition()).toEqual [0, 0]
+
       describe "when softTabs is enabled and the cursor is preceded by leading whitespace", ->
         it "skips tabLength worth of whitespace at a time", ->
           editor.setCursorBufferPosition([5, 6])

src/cursor.coffee

@@ -270,7 +270,14 @@ class Cursor extends Model
       @setScreenPosition(range.start)
     else
       {row, column} = @getScreenPosition()
-      [row, column] = if column > 0 then [row, column - 1] else [row - 1, Infinity]
+      newColumn = column - columnCount
+
+      if newColumn >= 0
+        column = newColumn
+      else if row > 0
+        row--
+        column = @editor.lineTextForScreenRow(row).length + newColumn + 1
+
       @setScreenPosition({row, column})
 
   # Public: Moves the cursor right one screen column.

src/editor.coffee

@@ -1636,8 +1636,8 @@ class Editor extends Model
     @moveDown(lineCount)
 
   # Essential: Move every cursor left one column.
-  moveLeft: ->
-    @moveCursors (cursor) -> cursor.moveLeft(moveToEndOfSelection: true)
+  moveLeft: (columnCount) ->
+    @moveCursors (cursor) -> cursor.moveLeft(columnCount, moveToEndOfSelection: true)
   moveCursorLeft: ->
     deprecate("Use Editor::moveLeft() instead")
     @moveLeft()