SWIG: update swiglib path

to external/common/share/swig
swig: update the Linux swig executable, !Mac needs update too

downloaded and built swig (2.0.10) on local machine and distribute the executable
swig file. Please build one for Mac and add it too!
remove libstdc++ license

we no longer link statically to libstdc++
see https://github.com/numenta/nupic/wiki/Configuration-and-Build-System
and NPC-59