Some improvements (#846)

* #833: do not require sudo on TravisCI

* #N/A: Add Python dev releases to TravisCI pipeline

Inspired by Brett Cannon's advise [1].

    1: https://snarky.ca/how-to-use-your-project-travis-to-help-test-python-itself/

* #837: try and kill proc and its children

* #N/A: show shell information on `thefuck --version`

* #N/A: omit default arguments to get_close_matches

* #842: add settings var to control number of close matches

* #N/A: remove `n` from the list of `get_closest`'s args

thefuck/entrypoints/main.py

@@ -8,6 +8,7 @@ import sys  # noqa: E402
 from .. import logs  # noqa: E402
 from ..argument_parser import Parser  # noqa: E402
 from ..utils import get_installation_info  # noqa: E402
+from ..shells import shell  # noqa: E402
 from .alias import print_alias  # noqa: E402
 from .fix_command import fix_command  # noqa: E402
 
@@ -20,7 +21,7 @@ def main():
         parser.print_help()
     elif known_args.version:
         logs.version(get_installation_info().version,
-                     sys.version.split()[0])
+                     sys.version.split()[0], shell.info())
     elif known_args.command or 'TF_HISTORY' in os.environ:
         fix_command(known_args)
     elif known_args.alias: