Implement event stream processing

Adds transparent event stream processing and statistics.
A new 3-tuple trace is introduced as `{Key, Op, Value}`, but
for backwards compatibility `{Key, Val}` implies `=` for `Op`
and `{Key, '*'}` remains as is in the case of wildcards.
A simplified query tree module is generated which reduces
redundant selection conditions to minimize filtering overhead.
9 files changed