Added utility function to get list of all function names in a object

Added utility method to get the list of function names in the object just like underscore of lodash _.functions or _.methods

Useful to create the Ramda plugins for example ramdangular

Its easy to get the list of utility functions Ramda has and make them available to the $rootScope in Angular

R.functions(R)  --> will return all the function names Ramda supports