Version 2 RC schema does not allow semanticType on encoding types

[donmendelson]

Although this was allowed in SBE v1.0, the current schema does not allow semanticType attribute on encoding types. This would be useful to map <type> to a FIX datatype. For example, a timestamp could be encoded in SBE as an integer (number of nanoseconds), but semantically it could represent UTCTimestamp.