Returns the current environment manager for the projex system.
        
        :return     <EnvManager>

def current():
        """
        Returns the current environment manager for the projex system.
        
        :return     <EnvManager>
        """
        if not EnvManager._current:
            path = os.environ.get('PROJEX_ENVMGR_PATH')
            module = os.environ.get('PROJEX_ENVMGR_MODULE')
            clsname = os.environ.get('PROJEX_ENVMGR_CLASS')
            cls = EnvManager

            if module and clsname:
                # check if the user specified an import path
                if path:
                    logger.info('Adding env manager path: %s' % path)
                    sys.path.insert(0, path)

                logger.info('Loading env manager: %s.%s' % (module, clsname))

                try:
                    __import__(module)
                    mod = sys.modules[module]
                    cls = getattr(mod, clsname)

                except ImportError:
                    logger.error('Could not import env manager %s', module)

                except KeyError:
                    logger.error('Could not import env manager %s', module)

                except AttributeError:
                    msg = '%s is not a valid class of %s' % (clsname, module)
                    logger.error(msg)

            EnvManager._current = cls()
        return EnvManager._current