Update the SDKs supported in CI.

It's not technically correct to say that 7.0 is no longer supported _at all_,
but we remove it from the list because we don't plan to test against it in CI.

We remove 5.1 because Travis no longer supports 5.1.
Add some missing escapes in `subliminal-test`'s documentation.
Use `instruments`' `-w` flag to enforce the simulator SDK & device type. (resolves #143)

This capability, added in Xcode 5.1, obviates the need to enable/disable
SDKs to force `instruments` to use a particular SDK for testing
(http://openradar.appspot.com/radar?id=3107401) and the need to
specify the `TARGETED_DEVICE_FAMILY` argument to force `instruments`
to use a particular device family for testing
(http://openradar.appspot.com/13607967).

The first components of the configurations respected by the `-w` flag
(the device types) are the same as the items listed in the iOS Simulator's
"Hardware -> Device" menu, so `subliminal-test` remains
backwards-compatible, despite its documentation changing.

Some references to iOS 5.1 have been updated in preparation for our
eventual dropping of 5.1 support (though we still do support it currently).
Deprecate the `--live` and `-login` password options of `subliminal-test`. (refs #176)

`instruments` may (and should) be "pre-authorized" using the instructions
at https://github.com/inkling/Subliminal/wiki/Continuous-Integration#faq.
Remove the `before_install` step from `.travis.yml`.

Travis initializes submodules for us as described here:
http://docs.travis-ci.com/user/build-configuration/#Git-Submodules
Don't try to unlink `appledoc` on Travis.

It's not (yet?) installed on the new 10.9 boxes.
Install `appledoc` from binary on Travis.

appledoc 2.1 uses GC and so cannot be compiled using Xcode 5.1,
so we download a pre-built version from the `gh-pages` branch
and manually install it.

The version was pre-built following the instructions [here][1] using
Xcode 5.0.2 and the `appledoc21` formula. I thought that maybe we
could install the resulting bottle [directly][2] but for some reason that
fails.

[1] https://github.com/Homebrew/homebrew/wiki/Bottles
[2] https://github.com/Homebrew/homebrew/wiki/Bottles#local-bottle-usage
Ensure Travis uses the latest version of `xctool`.

`xctool` 0.1.14 will fail to run Subliminal's unit tests.

Travis is supposed to have 0.1.15 installed--see
https://github.com/travis-ci/travis-ci/issues/2051#issuecomment-40817341.
Update the "terminal evaluation delay" for Travis' new VMs.
Merge pull request #181 from inkling/jeff/new_instruments

Update `subliminal-test` to take advantage of `instruments` 5.1.
When confirming the visibility of unknown objects, don't wait to resolve the elements.

The superclass' implementation looks like:

    [self waitUntilTappable:NO
          thenPerformActionWithUIARepresentation:^(NSString *UIARepresentation) {
        isVisible = [[[SLTerminal sharedTerminal] evalWithFormat:@"%@.isVisible()", UIARepresentation] boolValue];
    } timeout:0.0];

"Unknown objects" == objects of unknown classes like the accessibility elements
vended by `UIWebBrowserView`.

We shouldn't wait to resolve the element because `-isVisible` is supposed
to evaluate the current state.
Temporarily use UIAutomation to check visibility in non-portrait orientations. (refs #135)

As a workaround for the failure of our visibility routine.
Ensure that `-[SLDevice setOrientation:]` waits for the device to rotate.

The previous delay was not long enough for the animation to complete on the iPad.