A MetaValue provides a description of a property on a metanode.
int - (internal) Byte offset into a node's value buffer where this property data is stored
int - The type of value stored in this property
int - The number of values stored (e.g. 1 for a single value, 4 for an array of 4 values, etc)
int - The total number of bytes used by this property
vector - The data to initialise this property with for new node instances