Update unicode file

[pvdz]

https://gist.github.com/qfox/6118105

[pvdz]

It needs to be split up into two files. One containing only the unicode groups that are allowed as first char and the other one containing all the other ones. For the second char and onwards, two regexes will have to be checked. Luckily the check is in a cheap worst case part :/
Alternatively, I could maybe dynamically combine the two regexes although I'm sure whether that would make things faster (engine might optimize smaller regexes better?).

[pvdz]

I also need to do a thorough check for unicode characters. Oh joy.

[pvdz]

Reference: https://code.google.com/p/guava-libraries/source/browse/guava/src/com/google/common/base/CharMatcher.java?r=6162f3a87e733aed4308f5110528c2e4da89ed18#1339