Remove setup of `singlePoint` variable that is not used in some of the bar models.

Additionally, this variable was being assigned as a property on the global object (`window` in browsers) instead of being declared locally with a `var` statement.
Merge pull request #257 from JustinTArthur/remove-unused-global-singlePoint-var-assignments

Remove singlePoint variable that is assigned but not used in bar models.