Simplify printer whitespace and newline handling

Trying to handle all the whitespace and newline printing inside
printToken got overly complicated, and resulted in a few bugs in
the layout around comments and indentation that were hard to fix.
Rewrite the whitespace and newline handling to be handled directly
by the object printers, using requestSpace() to ensure whitespace
is inserted and requestNewline() to ensure a newline is inserted.

Also fixes unnecessarily left aligning all comments that contain
indentation, and fixes accidentally unindenting comments that are
the last token in their indented block.

Change-Id: I18707802726107cf0b6ec7de9b542d0ec1d2c0dd