Classic frequency and a couple of misc changes

During the package review for inclusion in Fedora, someone observed that:
- there was no copyright header in the `utils.cpp` and `utils.h` files
- the `COPYING.tables` file was worded confusingly

These are fixed in the first two commits of this pull request.

The rest is dedicated to fixing the « classic frequency ». This problem was uncovered by @antonyho, a few hours after I released IBus Cangjie 1.0 (which uses the classic frequency).