Some optimalisations

* Use `glyphicon-header` instead of `glyphicon-font`
* Don't prepend newlines if the heading is on the first line
* Only append newline to heading if a text was selected
* Don't insert a link if prompt returns empty or default
Merge pull request #25 from FokkeZB/patch-1

Some optimalisations
Adds an onFocus event similiar to the onBlur event
Merge pull request #27 from mightymax/master

Adds an onFocus event similiar to the onBlur event
Bump patch version
Merge branch 'master' into gh-pages
Add onFocus detail