Fix DUB package, source files are now compiled
Change length to uint32 to fix an issue on 32-bit
Fix default value usage on messages and enums

Fixes issue #15
Fix enum syntax to match protobuf specs

Rather than "EnumName.Value", protobuf specifies using only "Value"
Merge pull request #19 from Kelet/master

Some important fixes from @chickeaterbanana's fork