Text caching (not really)

In this commit I removed creating new instance of Text class everytime
when text was drawn. Now, when drawing begins, new instance of Text
class is created, and then drawing text is just changing properties of
it and at end of drawing this text is disposed. Simple enought, and I
think it speeded up things a bit. Also, removed empty try of getting
font kerning, what was not used anywhere in MeasureText sub.

Gwen.SFML.userprefs

@@ -0,0 +1,13 @@
+<Properties>
+  <MonoDevelop.Ide.Workspace ActiveConfiguration="Debug" />
+  <MonoDevelop.Ide.Workbench ActiveDocument="Gwen.SFML\Renderer.cs">
+    <Files>
+      <File FileName="Gwen.SFML\Input.cs" Line="1" Column="1" />
+      <File FileName="Gwen.SFML\Renderer.cs" Line="142" Column="22" />
+    </Files>
+  </MonoDevelop.Ide.Workbench>
+  <MonoDevelop.Ide.DebuggingService.Breakpoints>
+    <BreakpointStore />
+  </MonoDevelop.Ide.DebuggingService.Breakpoints>
+  <MonoDevelop.Ide.DebuggingService.PinnedWatches />
+</Properties>

Gwen.SFML/Renderer.cs

@@ -20,12 +20,13 @@ public class GuiRenderer : Base, ICacheToTexture
 		private RenderTarget _target;
 		private Color _color;
 		private Vector2f _viewScale;
-		//private SFMLTexture m_LastSampled;
-		//private Image m_SampleCache;
 		private RenderStates _renderState;
 		private uint _cacheSize;
 		private readonly Vertex[] _vertices;
 
+		//Some simple caching for text to draw
+		private Text _str;
+
 		public const uint CacheSize = 1024;
 
 		/// <summary>
@@ -46,11 +47,13 @@ public override void Begin()
 			var scaled = _target.MapPixelToCoords(new Vector2i(port.Width, port.Height));
 			_viewScale.X = (port.Width/scaled.X)*Scale;
 			_viewScale.Y = (port.Height/scaled.Y)*Scale;
+			_str = new Text ();
 		}
 
 		public override void End()
 		{
 			FlushCache();
+			_str.Dispose ();
 			base.End();
 		}
 
@@ -124,7 +127,6 @@ public override void FreeFont(Font font)
 		/// </returns>
 		public override Point MeasureText(Font font, string text)
 		{
-			// todo: cache results, this is slow
 			var sfFont = font.RendererData as SFML.Graphics.Font;
 
 			// If the font doesn't exist, or the font size should be changed
@@ -148,7 +150,6 @@ public override Point MeasureText(Font font, string text)
 
 			foreach (var cur in text)
 			{
-			    sfFont.GetKerning(prev, cur, (uint)font.RealSize);
 			    prev = cur;
 			    if (cur == '\n' || cur == '\v')
 			        continue;
@@ -177,15 +178,11 @@ public override void RenderText(Font font, Point pos, string text)
 					text += '\0';
 			}
 
-			var sfText = new Text(text, sfFont)
-			{
-			    Font = sfFont,
-			    Position = new Vector2f(pos.X, pos.Y),
-			    CharacterSize = (uint) font.RealSize,
-			    Color = _color
-			};
-		    _target.Draw(sfText);
-			sfText.Dispose();
+			_str.Font = sfFont;
+			_str.Position = new Vector2f (pos.X, pos.Y);
+			_str.CharacterSize = (uint) font.RealSize;
+			_str.Color = _color;
+			_target.Draw(_str);
 		}
 
         public override void DrawLine(int x1, int y1, int x2, int y2)