Modernize interfaces of core library classes

A number of libraries are not very X10-ish. They are close to Java libraries, which is fine, but they haven't been updated to X10 styling, which is a problem. In particular, classes should implement suitable operators as well as methods.

For example:

  map.getOrThrow(key)

is a perfectly good name for my favorite map extraction function. But for consistency with, say, cells, it could and should have an operator alias:

  map(key)

Certainly

 
   map(key) = value;

should be a synonym of

   map.put(key,value);

.

This should be done uniformly over the whole library. (Sure, I'll volunteer to do some of it.) For example:

  atomicInteger.get()

should have a synonym:

  atomicInteger()

.