Research Bugs

Research seems like it may have a few issues in the later parts of the tree that may usually go unvisited.  In Particular, the Plasma pistol's origin tech is level 6 combat with an unspecified level 4 that provides no advancement.

http://oi62.tinypic.com/2i92xqe.jpg

Suggest looking into the Tech tree to see if more little bugs like this can be found.
