Make `SLPickerViewTest` 64-bit compatible.
`-[UIView slAccessibilityIsVisible]` now reports an element's visibility on-screen,
regardless of window. (fixes #212)

That is, `-slAccessibilityIsVisible` will now properly report the visibility of views
in any window, even non-key windows; and `-slAccessibilityIsVisible` will now
properly report whether a view is visible on-screen, not merely within its window
(i.e. it will report `NO` if a view is occluded by the contents of a window above its window).

This removes the need for `SLPickerView` to use `UIAElement.isVisible`
(in order to match pickers used as input views).
Allow SLAssert methods to be called from non SLTest subclass methods
Merge pull request #215 from inkling/jeff/multiwindow_visibility

`-[UIView slAccessibilityIsVisible]` reports an element's visibility on-screen, regardless of window.
Incorporate PR feedback

Adding a comment to SLTest.h describing when SLAssert should be used
Renaming the static variables to use double underscores
Support for using a prebuilt app instead of building one (fixes #207)

This allows for decoupling of build CI and automation CI into two separate actions.
Merge pull request #217 from justinseanmartin/jmartin/allow-asserts-from-non-sltest-subclasses

Allow SLAssert methods to be called from non SLTest subclass methods
Merge pull request #218 from justinseanmartin/jmartin/allow-separated-build-from-testing

Add support for using a prebuilt app to allow decoupling of the tasks
Ensure that the status bar test has completely scrolled to top before finishing.

The app can crash due to a bad-access exception in `UIScrollView`
if a scroll view is deallocated before it finishes scrolling to top in response
to a scroll bar tap.

It's also simpler to test that the scroll view content offset changes as we expect
than that labels in the scroll view do/do not become visible.

Unfortunately, it appears as though Travis requires an explicit wait beyond
the wait-for loop.
Disable integration test transition animations when running in CI.

There's no one watching in that case, and disabling animations speeds up the tests
by about 40%.
Move the text field further above the keyboard.

This is the only explanation I can think of for
https://travis-ci.org/inkling/Subliminal/jobs/27273775,
plus the text field tests will look better, though this is still weird.
Merge pull request #209 from inkling/jeff/disable_transition_animations_in_CI

Disable integration test transition animations when running in CI.
Fix environment variable issue for testing on device
Remove export logic and update argument parsing flow per pull request feedback
Merge pull request #226 from hongkai/master

Fix environment variable issue for testing on device
Adding a better description to SLAlertHandler
Merge pull request #227 from justinseanmartin/jmartin/better-alert-handler-description

Adding a better description to SLAlertHandler
Fix the UIA path generated for Alert items by not removing its content view from the trimmed path
Make dismissByUser accessible always if desired
Better fix to the alert path without requiring private symbols