move isTrue checking into constants

Last thing we need is for a boolean check like this to start floating around everywhere without being cleanly contained in a proper location

src/Shader.py

@@ -38,6 +38,8 @@
 from OpenGL.GL.ARB.multitexture import *
 from OpenGL.GL.EXT.texture3D import *
 
+from constants import isTrue
+
 class ShaderCompilationError(Exception):
     pass
 
@@ -489,7 +491,7 @@ def checkIfEnabled(self):
                     value = Config.get("video","shader_"+i)
                     if value != "None":
                         if value == "theme":
-                            if Config.get("theme","shader_"+i).lower() in ["1", "true", "yes", "on"]:
+                            if isTrue(Config.get("theme","shader_"+i).lower()):
                                 value = i
                             else:
                                 continue

src/Theme.py

@@ -70,9 +70,6 @@ def valign(value, default='middle'):
         Log.warn('Invalid vertical alignment value - defaulting to %s' % default)
         return valign(default)
 
-def isTrue(value):
-    return value in ["1", "true", "yes", "on"]
-
 class Theme(Task):
 
     def __getattr__(self, attr):

src/constants.py

@@ -37,3 +37,8 @@
 # Screen sizing scalers
 SCREEN_WIDTH = 640.0
 SCREEN_HEIGHT = 480.0
+
+#set of values that define as true when loading string values from a file
+def isTrue(value):
+    return value in ["1", "true", "yes", "on"]
+