Support both SQL:2008 and PostgreSQL-style LIMIT clauses

"LIMIT 1" is just so much easier to type than "FETCH FIRST 1 ROW ONLY".

Signed-off-by: Morten Hustveit <morten.hustveit@gmail.com>
Allow changing the timestamp output format with SET TIME FORMAT

For example, you can use SET TIME FORMAT '%s'; to get the number of seconds
since UNIX epoch.

Signed-off-by: Morten Hustveit <morten.hustveit@gmail.com>
Added some support for JSON output

There's no escaping of strings yet, so the output can easily become broken.
The main advantage of JSON output is that it supports graph-like data, not just
2D tables.

Signed-off-by: Morten Hustveit <morten.hustveit@gmail.com>
Go back to using strftime for string formatting

Also use the format specified by SET TIME FORMAT to format plain TIMESTAMP WITH
TIME ZONE variables.

The way forward to optimize timestamp formatting is by adding proper LLVM code
generation for the specific format used.

Signed-off-by: Morten Hustveit <morten.hustveit@gmail.com>
Merge branch 'master' of https://github.com/mortehu/cantera-table

Conflicts:
	query-parser.y