Always use pyximport, since we now require cython.

This is optional and helps with development.  If we ever need/want to
support systems without Cython, this can be wrapped in a
try/except:pass block (and the .c files can be included in the
MANIFEST.in so that source distributions include them).

README.txt

@@ -15,6 +15,7 @@ Prerequisites:
   pip3 install -r requirements.txt
 
 Test:
+
   python3 setup.py nosetests
 
 Install:

nilmdb/server/__init__.py

@@ -1,13 +1,8 @@
 """nilmdb.server"""
 
-# Try to set up pyximport to automatically rebuild Cython modules.  If
-# this doesn't work, it's OK, as long as the modules were built externally.
-# (e.g. python setup.py build_ext --inplace)
-try: # pragma: no cover
-    import pyximport
-    pyximport.install(inplace = True, build_in_temp = False)
-except (ImportError, TypeError): # pragma: no cover
-    pass
+# Set up pyximport to automatically rebuild Cython modules if needed.
+import pyximport
+pyximport.install(inplace = True, build_in_temp = False)
 
 from nilmdb.server.nilmdb import NilmDB
 from nilmdb.server.server import Server, wsgi_application