This now throws early for an invalid call, rather than a currently confusing server message to users (see #724 fo details).

This is more consitent with our commands, enums, and redis docs themseleves.

fixed incorrect expectation for #900 - or... should it resolve at parse time? (decisions, decisions)

rework everything to use CommandBytes rather than having tons of byte[] all over the place; move Execute command checking earlier, adding ArgCount concept to allow full check

be evil, and make use of the innards of RedisValue to store array data (ref and count) when TypedRedisValue is multi-bulk

# Conflicts:
#	StackExchange.Redis.Server/RedisServer.cs
#	StackExchange.Redis.Server/RespServer.cs