Table tests; simplify; when browsers select span inside a `td`.
Throw error if textarea already belongs to an editor.
New `jQuery.getWymeditorByTextarea`.
Add a `.wym-initialized` to initialized textareas.
Added `WYMeditor.editor.teardown`, which tears down an editor.
Rewrote `setupWym` as `prepareUnitTestModule`.
Merge branch 'master' into qunit_module_preparation_rewrite
Don't explicitly teardown after multiple-instances tests.
Revert "Don't explicitly teardown after multiple-instances tests."

This reverts commit 766597171783ffafd0f91dae0ea35a4032edc29c.
Better options object handling in prepareUnitTestModule.
`prepareUnitTestModule`: options.amount -> options.editorCount
`prepareUnitTestModule`: Rearranged and commented on defaults object.
WYMeditor.editor.teardown -> .vanish & teardownAllWyms -> vanishAllWyms
Told JSHint about vanishAllWyms rename.
Fixed class name: .wym-tore-down -> .wym-vanished
WYMeditor.editor.vanish: Better docstring.
Use data-* attributes instead of classes for WYMeditor indication.
Documented `.vanish`.
Documented `jQuery.getWymeditorByTextarea`.
Document the `data-wym-initialized` attribute of the textarea.