Remove Id's String cast

[kevinresol]

This is mostly a trouble maker rather than a convenient function.

1. it subverts the type system (string is silently accepted without notice, mostly happen in refactors)
2. it crashes if the parsing is invalid

over the past few years I only get crashes from it but never really get any benefits.

[back2dos]

I think it might be there for allowing id in a query string and such.

[kevinresol]

I think in any case it should be explicitly parsed into int (so that exceptions can be handled) before passing to tink_sql.

[grepsuzette]

Perhaps we could have a @:deprecated on this cast from stringly to get more visibility how often it is used.