Add command line options

[StefanosChaliasos]

• auto Generate AQL queries and test orms.
• run Run specific AQL queries, use an sql script for generating the schema
• replay Run the given AQL queries on the given schemas. If no options are specified, this command inspects the .cynthia directory.
• generate Generate random AQL queries and schemas. It does not translate queries into ORM queries.
• clean Remove .cynthia directory

Add JSON serializer for AQL

[StefanosChaliasos]

Good job! General comments regarding functionality and CLI.

* When I run `replay` with no options, cynthia does not replay mismatches as expected.

You must specify orms and backends.

* When I run `replay` with `--all`, cynthia does not replay all queries as expected.

You should always specify orms and databases

* When I run `replay` with `--all`, `-s`, and `--mismatches`, cynthia does nothing.

Same here

* When I run `replay` and provide a mismatch that does not exist, cynthia should provide an message informing the user that this mismatch does not exist.

Okay, so we'll return an error in that case?

* Rename `auto` to `test`.

OK

* When I run the `run` command and provide the `.aql` file instead of `.aql.json` file, cynthia does not print any informative message.

I'll update the help message

The following options are not relevant to every sub-command.

When they are not relevant we simply ignore them :)

  -o, --orms <value>       ORMs to differentially test
  -d, --backends <value>   Database backends to store data (Default Value: sqlite)
  -S, --store-matches      Save matches
  --no-combined            Don't generate combined queries
  -r, --records <value>    Number of records to generate for each table