use std::runtime_error instead of std::exception

[thegrandpoobah]

Stippler throws std::exception errors. On Visual C++, std::exception takes a string argument in its constructor, but this is non-standard and was modified to work on Linux by removing the usage of e.what(). What should be done from the get go is to use std::runtime_error which has the string argument in the constructor as part of the standard.

[thegrandpoobah]

This is fixed in Release_20120224