Fix typo (__aj_error -> __aj_err) for fish shell.

Set OSTYPE correctly for fish wrapper.

OSTYPE was not being set correctly.  It is in bash, not sh.
    Since the value is unlikely to change, I read it once and
    stored it globally
Test logic was backward in jo function, causing error to always
    be printed, unless you did NOT specify a directory name.

Quote $XDG_DATA_HOME when setting error file.

Fixes #345.

I'm not sure if this is actually a bug in fish, but (test -d) with no argument returns true, and nonexistent environment variables return an empty string, so (test -d $XDG_DATA_HOME) returns true when $XDG_DATA_HOME isn't set.

Prior to making this change, I would get an error from dirname when opening a shell and an error from fish when cd'ing.

Fix for Issue 335

Fixes joelthelion/autojump#333

RFC: Handle `j -- -foo` (for bash and zsh only)

Ref: #310

Makes sure that autojump is sourced before running.

Fixes #255.

Add fish error logging.

Fixes #247.

Installs to /usr/local/share instead of /etc/profile.d.

Fixes #257, #267.

Fixes #256.

Fixes https://github.com/joelthelion/autojump/issues/312

For some reason, "command -v brew" by itself has started to output "/usr/local/bin/brew" whenever I start a new shell (in iTerm2 2.0 on OS X 10.9.4 with zsh, oh-my-zsh etc). This fixes it, and it looks like it's the recommended way anyway:

- http://unix.stackexchange.com/a/85250/4678
- http://www.cyberciti.biz/faq/unix-linux-shell-find-out-posixcommand-exists-or-not/

On Windows, we cannot reuse the temp.name to
reopen the file *unless* it has been closed
before [0].

This problem in turn made the `move_file`
request to fail, since the file was still
open at the time.

[0] https://docs.python.org/2/library/tempfile.html#tempfile.NamedTemporaryFile

Closes #299.

Due to the mixed testing between Python 2 and 3 and different string
implementations, there's no easy way to test Unicode stuff.

Closes #300.

Fix bad encoding

Completion and jumping for empty needles

In python3, string.encode returns a byte array like:
b'14.1:\t/home/felix/devel/autojump'
This stops autojump from functioning at all.