This is more a workaround than a fix: Windows 10 3D model fixing API refuses
to load a zip64 encoded 3MF. We need to get in touch with Microsoft on that
issue, for now the 3MFs generated for the Windows 10 3D model fixing API
will be limited to 4GB. Saving a bigger 3MF will fail.
1) All slicer's exceptions are now derived from Slic3r::Exception.
2) New exceptions are defined for slicing errors.
3) Exceptions are propagated to the Plater to show.
It remains to modify the slicing back-end to throw the new SlicingError
exceptions instead of std::runtime_error and to show the other exceptions
by a message dialog instead of a notification.
Removed libslic3r from the default include paths for all modules but
libslic3r. Now headers from libslic3r need to be included with an
explicit path (libslic3r/libslic3r.h etc)
Split the localization macros into I18N.{cpp,h}
