Changed zipline -> catalyst import paths

* Updated cython build scripts
 * Updated setup.py to to install catalyst package
 * Updated momentum example to use catalyst package
 * catalyst executable now supports loading pipelines from multiple bundles

etc/git-hooks/pre-commit

@@ -18,7 +18,7 @@ set -e
 stash_result=$(git stash --keep-index)
 
 # Run flake8 linting
-flake8 zipline tests
+flake8 catalyst tests
 # Run unit tests
 nosetests -x