Nyaa development helper (tool) (#324)

Add new tool for developing (lint/autopep8/isort/test)

New tool uses flake8 and isort for lint checks.
Deprecate existing tool (still works)
Update readme
Update Travis config

setup.cfg

@@ -1,3 +1,16 @@
+[flake8]
+max_line_length = 100
+# The following line raises an exception on `pip install flake8`
+# So we're using the command line argument instead.
+# format = %(path)s [%(row)s:%(col)s] %(code)s: %(text)s
+
+[pep8]
+max_line_length = 100
+pep8_passes = 2000
+in_place = 1
+recursive = 1
+verbose = 1
+
 [isort]
 line_length = 100
 not_skip = __init__.py