Fixed browserpool not resetting panel after gmod update

Shoutout to CaveeJohnson for the original fix 🎉"

lua/autorun/includes/modules/browserpool.lua

@@ -63,7 +63,7 @@ local numRequests = 0
 -- Default URL to set browsers on setup/teardown.
 -- @type String
 --
-local defaultUrl = "about:blank"
+local defaultUrl = "data:text/html,"
 
 ---
 -- JavaScript code to remove an object's property.
@@ -97,6 +97,9 @@ local function setupPanel( panel )
 	-- Browser panels are usually manually drawn, use a regular panel if not
 	panel:SetPaintedManually(true)
 
+	-- Fix for panel not getting cleared after 3/2017 update
+	panel:SetHTML( "" )
+
 	-- Set default URL
 	panel:OpenURL( defaultUrl )
 

lua/mediaplayer/controls/dmediaplayerhtml.lua

@@ -37,7 +37,7 @@ function PANEL:Init()
 	self.Callbacks = {}
 	self.MouseActions = {}
 
-	self.URL = "about:blank"
+	self.URL = "data:text/html,"
 
 	--
 	-- Implement a console - because awesomium doesn't provide it for us anymore