Deactivate tooltip on tab by default.

Codepath is **not** removed by this.
Update some example notebook with Shift-Tab
Remove tooltip on tab logic
make close-and-halt work on new tabs in Chrome

this is not possible in Firefox, as new tabs/windows which were *not*
opened via a script ( window.open call ) are not allowed to be closed
via window.close and will yield a message like

--
[11:50:59.691] Scripts may not close windows that were not opened by script. @ http://localhost:8888/static/notebook/js/menubar.js:105
fix: allow JS test to run after shutdown test

shutdown notebook test closes casper browser, here we re-instatiate it
after the test
Switch default IPython directory back to ~/.ipython

As discussed at the dev meeting, we care more about a consistent default
across platforms than half-heartedly following the XDG specs.
Update tests for IPython.utils.path
don't delete casper instance on shutdown test

a lunch conversation with @minrk and @takluyver lead me to just make a
popup and have it be closed, instead of having to reorder the test suite
so that this test always runs last. Now it doesn't matter what order the
test suite runs in, and gives us a pattern for testing window closing
behavior should we need it elsewhere.
Update doc references to .config/ipython
protect against broken repr in lib.pretty
test bad repr
be really super ultra safe about reprs

don't trust exception strings or class attributes.

adds _safe_getattr, used in a few higher level places to protect against bad objects
test really bad repr
update man page to reflect XDG disrespect :)
remove XDG link
add note to "what's new"
a couple of more stray XDG / .config references
Merge pull request #8 from ivanov/ipython-dir-default

main change is adding a what's new entry
Merge pull request #4451 from ivanov/shutdown-js

fix: allow JS test to run after shutdown test
Bundled path.py should not modify the os module