Use eraseScreen instead of clearScreen

app/assets/javascripts/player/vt/ansi_interpreter.js.coffee

@@ -249,10 +249,10 @@ class AsciiIo.AnsiInterpreter
         if action is "h"
           # Save cursor position, switch to alternate screen buffer, and clear screen.
           @cb 'switchToAlternateBuffer'
-          @cb 'clearScreen'
+          @cb 'eraseScreen'
         else if action is "l"
           # Clear screen, switch to normal screen buffer, and restore cursor position.
-          @cb 'clearScreen'
+          @cb 'eraseScreen'
           @cb 'switchToNormalBuffer'
 
   parseParams: (params) ->

app/assets/javascripts/player/vt/screen_buffer.js.coffee

@@ -61,9 +61,6 @@ class AsciiIo.ScreenBuffer
   clearChanges: ->
     @dirtyLines = {}
 
-  clear: ->
-    @lineData.length = 0
-
   getLine: (n = @cursorY) ->
     throw "cant getLine " + n  if n >= @lines
 

app/assets/javascripts/player/vt/vt.js.coffee

@@ -31,9 +31,6 @@ class AsciiIo.VT
 
   # ==== Screen buffer operations
 
-  clearScreen: ->
-    @buffer.clear()
-
   switchToNormalBuffer: ->
     @buffer = @normalBuffer
     @updateScreen()