Focus mode

[olivierkes]

As suggested by @hugo-id in #234 (comment) :

[olivierkes]

Just added focus mode!

You can chose between "Line" or "Paragraph".

Supports Markdown markup:

And works in full screen mode:

[olivierkes]

Added Sentence mode, based on a suggestion by @thoronaug here #234 (comment).

Tell me if this is not how you expect it to behave.

[thoronaug]

Awesome! It's exactly what I mean. It works perfectly.
Thank you!

[thoronaug]

I've discovered an error in Sentence Focus mode. When starting a sentence with a "-" sign, everything is grayed out after the first sentence end (dot, ! mark, etc).

If I write:
- Hello!
It works ok, and the word Hello! is focused. But if I keep writing in the same line:
- Hello!Who are you?
the whole line appears unfocused.

EDIT: Also in line focus mode, when you start the line with a "-" sign and you type beyond the end of the line (until the line feed), the second line appears grayed out too.