Integration libHeinz into Steca
This MR introduces libHeinz as a dependency to Steca as a preparation for the MR of Issue #106. This is necessary since additional math operation are required for that upcoming MR. Because the basic implementation of vector and matrix structs were already used, some additional code needed to be replaced with libHeinz.
Also one unit test has been replaced/updated
this closes issue #107 (closed)