Improve position tracking in compiler
Improve position tracking in compiler

Improve error position reporting by storing copy of current source
position when parsing literals such as strings, arrays, objects and so
on. This prevents EOF being reported as the position of the error when
any of these literals is unterminated. Also begin counting columns from
1 instead of 0.

RauliL/plorth,RauliL/plorth,RauliL/plorth,RauliL/plorth,peelonet/plorth