Two changes to the global load() method:

* the default scope of the executed module is now the current scope (this)
  rather than the global object - solves the problem with redefining const vars
  if load()ing same include module more than once in a context. This will
  likely defeat modules (like S3 Shell) that use this old behavior to create
  session-persistent objects (another technique will need to be utilized).
* an optional scope object parameter can be specified as the first parameter
  specifying the context in which to execute the module (default = this)