Revert "Replace toCamelCase with _.camelCase, see https://github.com/phetsims/phet-core/issues/72"
Revert "Replace toCamelCase with _.camelCase, see https://github.com/phetsims/phet-core/issues/72"

This reverts commit fd7b26c73656825efcf569b4b98acf50cc9b1de3.

phetsims/chipper,phetsims/chipper,phetsims/chipper