* Switched hashtables.h over to std::undordered_map from boost version.
* Added new macros DECL_VEC_FOR_SWIG() and DECL_MAP_FOR_SWIG() in macros.h.
These along with future DECL_HASH_FOR_SWIG() unify the declaration to swig
and C++ so that the resultant type name is common in both languages, and
the types AGREE.
* Fixed swigging of NETINFO_ITEM and NETINFO_LIST via magic.
* Newly exposed (python wrapped) are: D_PADS, TRACKS (was TRACK_PTRS),
NETNAME_MAP, NETCODE_MAP, wxString (without constructor purposely, read
comment in wx.i), MARKERS, ZONE_CONTAINERS, NETCLASSPTR, KICAD_T types.
* std::vector<SOMETHING*> tends to end up named SOMETHINGS in C++ and python.
Having the name consistent between like types is helpful, and between
languages. std::map<> ends up as SOMETHING_MAP.
* NETINFO_LIST::m_netNames and NETINFO_LIST::m_netCodes are now std::map
instead of hashtables, because swig does not yet support std::unordered_map.
* You can now get to any netclass or net info. NETNAMES_MAP and NETCODES_MAP
are traversable basically the same as a python dictionary using a python
string (not wsString) as the key! The wxString typemap converts python
string to wxString before the lookup happens. Iteration also works.