Enhance HSQLDB stored routine support

[MMatten]

Supersedes #553, #541 and #535.

[javornikolov]

@MMatten, that looks good to me 👍. Unless you have more changes to add - I think we can merge it?

[MMatten]

@javornikolov I've nothing else to add.

[MMatten]

I'll close down the other PRs.

[javornikolov]

@javornikolov I've nothing else to add.

Cool! I'm merging it then ... Thanks a lot @MMatten !

I'll close down the other PRs.

In general this can be also done by closes #nnn comment in the PR (https://help.github.com/articles/closing-issues-via-commit-messages/). Anyway - not a big deal to do it manually :-)