feat(locators) Add map() function to element.all

Added a map function to element.all to apply a function to each element and return the result of the transformation.

Closes #392
feat(global): export By (== by) on the global for use with coffeescript (or others who prefer it)
feat(config): allow CoffeeScript configuration files

Require CoffeeScript in the cli file to enable CS configuration and spec
files.

Possibly fixes #38
refactor(config): amend to coffeescript - do not require, but allow