fix: don't include untouched files in build output

[bouclem]

Fixes #237.

Two bugs were causing unmodified files to leak into build output (e.g. user reports gui/items.png, terrain.png, ItemArmor$EnumArmorMaterial.class, TileEntityFurnace$1.class ending up in the zip even though they weren't touched after the MD5 update).

Bug 1 - Inner classes always extracted in TaskReobfuscate

The FileUtil.extract filter stripped $... from the obfuscated entry name, then looked the result up in reversedNames (a map keyed by obfuscated outer-class names). Inner classes have entries like ItemArmor$EnumArmorMaterial, and stripping the inner suffix gives ItemArmor - which isn't in the obfuscated map. The lookup returned null, the code fell back to using the obfuscated name as the deobf name, the hash lookup also missed, and extract was forced to true unconditionally.

Fix: resolve the deobfuscated name first (try the full entry name, then fall back to the outer class), then strip the inner-class suffix from that deobf name to build the hash key.

Bug 2 - Asset files never compared against MD5

TaskBuild walked every non-class file under bin/ and packed it into the build zip with no hash check, so any asset that was just a copy of the original (e.g. an unmodified terrain.png left over from the source layout) was always bundled. TaskUpdateMD5 already records hashes for these files, the build step just wasn't reading them.

Fix: in TaskBuild, read the original MD5 file once and only include assets whose current hash differs from the recorded one (or that have no recorded hash, i.e. genuinely new files).

Testing

• gradlew build passes
• No new dependencies
• Same code path on the happy case (modified files still get packaged); only unmodified files are now excluded