BUKKIT-45, Fire EntityChangeBlockEvent for priming TNTs

Found at least 7 issues on it, and 4 PRs (including this one), not one got accepted.
This implementation is similar to what you did with falling sand blocks, using an existing _EntityChangeBlockEvent_ with the entity being the _EntityTNTPrimed_ and new type = _AIR_.
Minimalistic, simple solution you should not over-think about and just __PULL__!

Here's some leakies (only from page 1 and 2 searching for TNT):
https://bukkit.atlassian.net/browse/BUKKIT-286
https://bukkit.atlassian.net/browse/BUKKIT-2610
https://bukkit.atlassian.net/browse/BUKKIT-45