Make link platform-specific

It didn't work on windows in current state

Author: DarkFenX

gui/mainFrame.py

@@ -245,7 +245,11 @@ def ShowAboutBox(self, evt):
                                      "\nwxPython: \t" + wx.__version__ +
                                      "\nSQLAlchemy: \t" + sqlalchemy.__version__,
             700, wx.ClientDC(self))
-        info.WebSite = ("http://forums.eveonline.com/default.aspx?g=posts&t=247609", "pyfa thread at EVE Online forum")
+        if "__WXGTK__" in  wx.PlatformInfo:
+            forumUrl = "http://forums.eveonline.com/default.aspx?g=posts&t=247609"
+        else:
+            forumUrl = "http://forums.eveonline.com/default.aspx?g=posts&t=247609"
+        info.WebSite = (forumUrl, "pyfa thread at EVE Online forum")
         wx.AboutBox(info)