Fixed function `subset` not being able to return a scalar value `null` or `undefined` (see #205)
Merge branch 'develop'

Conflicts:
	HISTORY.md
Merge branch 'develop'
Using format precision=14 in stringified output of Help
Roadmap updated
Merge branch 'master' into develop
Removed references in documentation to the "distribution" function
Fixed #210: Disabled array notation for ranges in a matrix index the expression parser