Added new file connectivity.i to expose CONNECTIVITY_DATA to
python. enables access to d_pads from nets.
Added typemap to board_connected_item.i. since board_connected_item
doesn't use virtual inheritance, when returning a std::list of these
items, the typemap populates the return list with the child
types. This enables python scripts to use the full interface of those
classes (pad, track, zone)
Added typeinfo.i to enable passing a list of KICAD_T values to methods
GetNetItems. This list acts as a query filter. typeinfo.i is included
from pcbnew.i right after kicad.i (instead of in board.i like the
others) typeinfo.h is already being included kicad.i so to ensure the
typemap(s) are properly applied I put them next to each other.
The two new files (typeinfo.i and connectivity.i) were added to
pcbnew's CMakeLists.txt as dependencies.