Provide NBT contstants

[reoseah]

In my opinion, it's common enough to be in Rift under some util package. The codes as they appear in Forge for reference:

public static final int TAG_END = 0;
public static final int TAG_BYTE = 1;
public static final int TAG_SHORT = 2;
public static final int TAG_INT = 3;
public static final int TAG_LONG = 4;
public static final int TAG_FLOAT = 5;
public static final int TAG_DOUBLE = 6;
public static final int TAG_BYTE_ARRAY = 7;
public static final int TAG_STRING = 8;
public static final int TAG_LIST = 9;
public static final int TAG_COMPOUND = 10;
public static final int TAG_INT_ARRAY = 11;
public static final int TAG_LONG_ARRAY = 12;
public static final int TAG_ANY_NUMERIC = 99;