Remove needless CallableArrayType and CallableStringType

[klimick]

Since this can be expressed through:

• String callable: callable&string
• Static array method: callable&list{class-string, string}
• Instance array method: callable&list{object, string}

Does it make sense to add factory methods for callable-string and callable-array to the types ?
These are quite rare types and the chance that someone will ever use these methods is small.