Use `noautonamedirs` with Zsh aliases

Fixes https://github.com/joelthelion/autojump/issues/312
Fix flake8 errors.
Use ternary.
Merge branch 'master' of github.com:joelthelion/autojump
Always append to error log.
Detect user shell as opposed to login shell.

Fixes #256.
Minor doc fix.
Installs to /usr/local/share instead of /etc/profile.d.

Fixes #257, #267.
gitignore: __pycache__
Merge pull request #321 from wting/install_to_usr_local_share

Installs to /usr/local/share instead of /etc/profile.d.
Add fish error logging.

Fixes #247.
Merge pull request #320 from wting/add_fish_error_logging

Add fish error logging.
Makes sure that autojump is sourced before running.

Fixes #255.
Merge pull request #319 from wting/check_autojump_sourced

Makes sure that autojump is sourced before running.
Handle `j -- -foo` (for bash and zsh only)

Ref: #310