Umka 0.6

• Stricter equivalence rules for declared types
• Equivalence rules for functions no longer require parameter names to match
• Interfaces can be converted back to non-pointer types
• Pointers to pointers cannot be stored in interfaces
• All structures have natural alignment
• Support for sizeof(T) and std.system(command)
• Storing pointers as void * rather than int64_t in VM stack
• Static storage size is no longer required in umkaInit()
• Bug fixes
• Tested on 32-bit PowerPC and SPARC