Mega.co.nz will not be supported until _they_ can provide a reasonable JavaScript-only API. They currently provide only C++ and C# SDKs and do not support OAuth. You should complain to Mega about their poor developer support.
If Tusk could support Mega, it would. Please feel free to comment on https://github.com/subdavis/Tusk/issues/153 if this did not answer your question.
If possible, please update your review with the understanding that Mega support is not feasible.
