Add break and continue keywords when inside a method
Cover more cases with dot completion

Leading .dot completion now works even if the "." is not the first
non-whitespace character in the line.  Some cases where it doesn't
work still exist but most are covered.

A single method call should show correct members now.
foo.bar(a, b)._
will show members for the return type of the bar method. There are
plenty of cases where this doesn't work quite right.