updated get_calling_environment() documentation, scripts are now cached by default again
beak rewrite, scripts look very different now ;-)
scripts can now implement their own __call__(), __iter__() and __str__() method, updated resource scripts
updated resource scripts, fixed beak.targets module, Environments now also have dependencies, added Session.execute_env_routine()
added option to not execute external targets in BaseTarget.execute_routine()
added -c, —-clean argument to beak.__main__
a Script may now define a variable __all__ that is used when no target is specified via the command-line
ScriptEnvironment.provide_interface() is now called from the ScriptEnvironment constructor rather than Runtime.execute_script()
update README.md