Change to non-snapshot Bukkit 1.7.9-R0.1 release

No real need for snapshots here, just stick with the release build now.
Add the beginning of a non-enum org.bukkit.Material replacement

enums don't jive well with the dynamic extensibility desired here, so
replace org.bukkit.Material with a somewhat-compatible class instead.

Tested with deathcap/SamplePlugin@d59ea512e544b912cb500f1613a3ee1b7ff518c0
getMaterial(), switch(), ordinal(), values() same results
Hack to extend java.lang.Enum with a class

Surprisingly this works. Using a placeholder class name, replaced at build.
Stub out most of the Material API calls
Publicize the Material constructor
Set material fields dynamically (but can't create)
Add duplicate material index check
Set material fields to UNSUPPORTED until they are initialized later

Not all materials might be supported, and new materials might be added
without fields
Fix getMaxDurability definition
Add placeholders for all material API fields