Consolidate multiple "my_getline" functions
This issue was created automatically from an original Mantis Issue. Further discussion may take place here.
Because VC6 does not include std::getline(), a local "my_getline" function is defined in several .cxx files in VTK to provide this functionality. This function should be put in a separate file, possibly in IO, so code is not duplicated. Additionally, we should redefine getline in a common header to generate an error since it is not supported on all compilers.