In this commit, we implement zlib encoding and decoding for the channel
range queries. Notably, we utilize an io.LimitedReader to ensure that we
can enforce a hard cap on the total number of bytes we'll ever allocate
in a decoding attempt.
In this commit, we fix a slight bug in the parsing of encoded short
channel ID's. Before this commit, we would always assume that the remote
peer was sending us the sorted+encoded variant of the short channel
ID's. In the case that they weren't (as there isn't yet a feature bit),
we would assert this check and fail early as atm we don't support any
sort of compression.
