builder: Remove local variables detection from the builder

We will do it at later stage.
Add locals: a new defered locals marking routine
eliminator: Rewrite into slotworks, remove a local variables handling

Require loop-ends swapped
unwarper: fix a loop unwarping in case of swapped loop ends
Remove the _varinfo attribute from the Identifier node
nodes: Add a function infrastructure to support local markings
nodes: Traverse the Assignment in the correct order
debuginfo: Fix slots being marked as locals after their scope end
writer: allow single-letter variables to be global too =)
writer: fix a skip routine being a bit too proactive in skipping stuff
writer: Output strings with slash (\) with double-slash (\\) instead
main: now use it all already!