Bump mc version in travis and textures.py error msg. also force rebuild

.travis.yml

@@ -4,7 +4,7 @@ python:
   - "2.7"
   # - "3.2"
 env:
-  - MC_VERSION=1.8
+  - MC_VERSION=1.9
 before_install:
   - wget https://raw.githubusercontent.com/python-pillow/Pillow/master/libImaging/Imaging.h
   - wget https://raw.githubusercontent.com/python-pillow/Pillow/master/libImaging/ImPlatform.h

overviewer_core/src/overviewer.h

@@ -26,7 +26,7 @@
 
 // increment this value if you've made a change to the c extesion
 // and want to force users to rebuild
-#define OVERVIEWER_EXTENSION_VERSION 49
+#define OVERVIEWER_EXTENSION_VERSION 50
 
 /* Python PIL, and numpy headers */
 #include <Python.h>

overviewer_core/textures.py

@@ -310,7 +310,7 @@ class Textures(object):
                 if verbose: logging.info("Found %s in '%s'", filename, path)
                 return open(path, mode)
 
-        raise TextureException("Could not find the textures while searching for '{0}'. Try specifying the 'texturepath' option in your config file.\nSet it to the path to a Minecraft Resource pack.\nAlternately, install the Minecraft client (which includes textures)\nAlso see <http://docs.overviewer.org/en/latest/running/#installing-the-textures>\n(Remember, this version of Overviewer requires a 1.8-compatible resource pack)\n(Also note that I won't automatically use snapshots; you'll have to use the texturepath option to use a snapshot jar)".format(filename))
+        raise TextureException("Could not find the textures while searching for '{0}'. Try specifying the 'texturepath' option in your config file.\nSet it to the path to a Minecraft Resource pack.\nAlternately, install the Minecraft client (which includes textures)\nAlso see <http://docs.overviewer.org/en/latest/running/#installing-the-textures>\n(Remember, this version of Overviewer requires a 1.9-compatible resource pack)\n(Also note that I won't automatically use snapshots; you'll have to use the texturepath option to use a snapshot jar)".format(filename))
 
     def load_image_texture(self, filename):
         # Textures may be animated or in a different resolution than 16x16.