updated stack representation. line is a vector of shared pointers. instructions are in op_node.h and are represented by a base class, node, with polymorphic eval function.
Update .gitignore

added vsp
slight fix to op nodes
Merge branch 'stack' of https://github.com/lacava/develep into stack
fixed mutation operator, age fitness.
added makenewcopy.cpp to address shared_ptr expansion. now new objects are created when individuals undergo breeding so that there are not two individuals accessing the same object in memory.
added printlastpop and sort function in tribe class
hanging files deleted
Merge branch 'master' of https://github.com/lacava/develep