1.11.0

Fixed a crash on compiling empty programs at low optimisation levels.

The strip argument is now -s, consistent with other compilers, and
binaries are no longer stripped by default.

Stripping is now done during linking, rather than shelling out to
strip. This is faster and more robust.

Improved dead code elimination after multiply loops, e.g. [>++<-][-]
is equivalent to [>++<-].