Missing possibility to escape quotes within a literal

[wjzijderveld]

At the moment it's impossible to search for a string with both single and double quotes in it with SQL2. And I suspect it might be impossible at all to have double quotes, but haven't a hard test for it yet.

[dbu]

with #199, it became possible to correctly escape strings in strings. you can use \" or "" to quote a double quote, and \' or '' for single quotes.