Runnable short title

[duncanbeevers]

Fixes #1230

In this approach, rather than modifying the hook titles at failure time, a run-time shortTitle method is exposed on Suite, Runnable, and Hook.

In the case of a Suite and a Runnable, this method returns the current value of title attribute.
In the case of a Hook running in the context of a test, the shortTitle will reflect both the hook's own title and the title of the currently-executing test.

[dasilvacontin]

Needs tests asserting this works.

[duncanbeevers]

Added basic specs for shortTitle, and the existing fullTitle tests continue to pass.

[boneskull]

Some discussion in #1447.

[duncanbeevers]

@boneskull In #1447, you ask "Practically, how does a hook receive a title?"

The crux of the issue is that titles were all set when objects such as Runnables and Hooks were initialized. Since Hooks were run multiple times, the static title failed to reflect the context in which it was being run.

The first part of this refactor was to retrieve the Runnable and Hook titles through a method rather than a property, so that it could be retrieved dynamically by the Reporters.

In the case of Runnables, this method simple proxied to the existing static title property.
In the case of Hooks, more dynamism is introduced. First the Hook's own, original title is retrieved, followed by the title of the Runnable in whose context the Hook is running. The two are concatenated, resulting in a Hook shortTitle that changes as each test is run.

[jbnicolai]

Is there anyhting holding of a merge of either this or #1447? @boneskull @danielstjules? LGTM :)

@duncanbeevers thanks for the effort!

[jbnicolai]

Closing in favor of #1447