Alternator and CDC, apart from enabling their experimental features,
need to have their schema extensions registered. This patch adds missing
registration of schema extensions to cql_repl, so that cql tests written
with Alternator or CDC in mind will properly work.
cql_repl is a simple program which reads CQL from stdin,
executes it, and writes results to stdout.
It support --input, --output and --log options.
--log is directed to cql_test.log by default.
--input is stdin by default
--output is stdout by default.
The result set output is print with a basic
JSON visitor.
