Adds pre-commit config to run various lintersci_improvements

This ads black, isort, pyupgrade, and flake8 to pre-commit-config.yaml
There are also some small changes to travis.yml and tasks.py to reduce
some repeated configurations that should be consolidated into
setup.cfg. Most other changes are automated by the linter scripts.

1 files changed, 1 insertions, 0 deletions

diff --git a/examples/arg_print.py b/examples/arg_print.py
index dbf740ff..6736c74f 100755
--- a/examples/arg_print.py
+++ b/examples/arg_print.py
@@ -64,5 +64,6 @@ class ArgumentAndOptionPrinter(cmd2.Cmd):
 
 if __name__ == '__main__':
     import sys
+
     app = ArgumentAndOptionPrinter()
     sys.exit(app.cmdloop())