update Unicode tables

[stevengj]

As discussed in JuliaLang/julia#7582, utf8proc currently has the Unicode 5.0 tables. It would be good to import the database from Unicode 7.

The file data_generator.rb is a Ruby script that outlines how the Unicode 5 tables were imported, though looks like it is not fully automated. The first step would be to figure out how to re-run that on the Unicode 5 table in order to reproduce the current utf8proc_data.c. This will verify that we are importing the data correctly before we move to the new Unicode 7 data tables.

[stevengj]

I'm tempted to re-write the scripts in Julia, as I don't know Ruby; they don't look very complicated. But we should see how difficult they are to run on the Unicode 5 data first.