remake pgfunc to accept any language functions

[eugwne]

• now possible to call plpgsql(and other) functions
• added tempmemory context for function calls
• added new tests
• added options as a second parameter for pgfunc

if pgfunc uses is not internal than second arg should be used: secod arg is table with options {only_intermal = false, throwable = false} if function is not internal, than when throwable == true then pg_try pg_catch are used inside