rasql type management syntax

[Dimitar Misev]

We should consider whether the curly braces and comma in type definitions should be dropped, e.g. this example:

CREATE TYPE RGBImage
UNDER MARRAY {
RGBPixel
} , [*:* ,*:*]

would rather be:

CREATE TYPE RGBImage
UNDER MARRAY RGBPixel [*:* ,*:*]

We should check if they are optional in the SQL standard. We could make them optional in any case.