Never ever make methods called by Unity private if there is inheritance.

A private method that is called from outside the class not via a delegate
is in itself a violation of the encapsulation concepts of the language.
Rewrite container cost computation to cache the cost in the config nodes.

Also, instead of custom code, try using the function KSP itself uses
to compute costs when recovering a vessel.
Remove IScienceDataContainer and instead work on the config node level.

This interface allows infinite retransmission by clicking on the antenna
and choosing Transmit Data, and it is not even used for recovery.
Merge pull request #119 from angavrilov/master

Rewrite cost and science recovery to make it more efficient.