Added LazySeq built from Iterator
Polishing Build script

- sub build scripts moved to bld/
- build artifacts moved to out/
- Bldit renamed ot Build (add ./ to PATH for easy start)
Trying source watching for continuous build
Adding list of tasks at Build startup
Correcting compilation warnings

Added -Xlint:all to javac task and corrected warnings or suppressed
those I can't correct, by definition of a cast.

Because of non-parametrizable arrays, I had to change Seq.of(Y... args)
and "unroll" it manually by overloading 4 times. This solution is not
really scalable to all concrete data structures unfortunately.