adds pip setup script, updates gitignore

- pip setup.py is provided to allow installs via pip
  this includes a brief package description and install
  dependencies
- bump is now moved to a subfolder bump with __init__
  as this is a package setup requirement
- gitignore now ignores any tar'ed files and any
  pycaches

.gitignore

@@ -1,2 +1,4 @@
-__pycache__/*
+*__pycache__/*
 .bump*
+*.tar.gz
+*.egg-info/*