Update to more recent version of Unicode

[H2CO3]

This still uses Unicode 7.0.0 which causes serious discrepancies in the handling of e.g. XID_Start and XID_Continue properties. For instance, ^\p{XID_Continue}$ doesn't match U+17828, whereas unicode-xid's UnicodeXID::is_xid_continue() correctly returns true for this code point.

[H2CO3]

Awesome! 🍾 👍 I don't want to sound like a pain, but is it possible that we'll see a 0.2.3 release soon with this – quite important – improvement? 😃

[BurntSushi]

I'm not sure I appreciate the importance here, but I'd like to get a couple more of the outstanding PRs merged first before cutting a release.