Single completion add blank only at end

[tkruse]

The CandidateListCompletionHandler has an option to add a blank after a single full completion. However the code limits this to situations where the cursor is at the end of the buffer. I believe the behavior should be the same when the cursor is anywhere in the buffer. This also requires some more attention to the existing chars in the buffer, to avoid creating a second blank where one existed already.

[gnodet]

I think we need to make that easily pluggable / configurable.
I've currently tried to mimic bash behaviour, but zsh behaves differently for example.

[tkruse]

I find that there are almost endless possibilities to configure corner cases in completion. Providing switches for each alternative would make things very confusing and would allow for many bugs. So I would suggest for jline to generally provide only a single best-effort alternative, and allow variations via subclassing. In my PR #215 I can add some protected method calls to make overriding the behavior easier.

[tkruse]

In #215 I added a commit that uses two protected methods to change the default behavior.