Initial SIMD demos life and earth for PNaCl.

native_client_sdk/src/examples/demo/earth_simd/example.dsc

 {
-  'TOOLS': ['newlib', 'glibc', 'pnacl'],
+  'TOOLS': ['pnacl'],
   'TARGETS': [
     {
-      'NAME' : 'earth',
+      'NAME' : 'earth_simd',
       'TYPE' : 'main',
       'SOURCES' : [
         'earth.cc'
       ],
      'LIBS': ['ppapi_simple', 'nacl_io', 'sdk_util', 'ppapi_cpp', 'ppapi', 'pthread']
     }
   ],
   'DATA': [
     'earth.jpg',
     'earthnight.jpg',
     'example.js',
   ],
   'DEST': 'examples/demo',
-  'NAME': 'earth',
-  'TITLE': 'Multi-Threaded Earth Demo',
+  'NAME': 'earth_simd',
+  'TITLE': 'Multi-Threaded SIMD Earth Demo for PNaCl',
   'GROUP': 'Demo'
 }