This commit creates the class for an SDS message channel, including
buffers for outgoing and incoming messages. Adds logic for sending
messages, receiving messages, delivering messages, and reviewing
acknowledgement status of messages. Also adds byte serialization
for bloom filters.
Uses an array of bigint to store sufficient bits in bloom filter.
Updates all arithmetic to explicitly cast to bigint where necessary.
Makes the hashn function for bloomfilter a parameter.
Adds an implementation of hashn generated using nim compiler.
Adds tests.
Adds a new package for the browser implementation of scalable data
sync. Ports some of the nim implementation of bloom filter to ts.
Adds protobuf definition for SDS messages.
