Dump config file

Add functionality to dump config file when calling a ConfigCommand

Fixes #61 (closed)

bob/extension/data/test_dump_config.py

+## Configuration file automatically generated at 05/07/2018 for cli test.
+
+
+## Path leading to test blablabla.
+## Option: -t, --test [default: /my/path/test.txt]
+# test = /my/path/test.txt
+
+
+
+