implement deflateParams, deflateGetDictionary, inflateGetDictionary

[UselessMnemonic]

Implements deflateParams closely to the original source.
Implements deflateGetDictionary, inflateGetDictionary with a slightly different interface:

• Instead of accepting an out-parameter for dictLength, return a tuple of the status code and the dictLength
• Limit the dictLength to the length of the dictionary parameter, whereas the original source makes no such concession

An alternative to the above is to accept some Uint32Array as the out parameter.