This reverts commit 5cd07648fd.
The separators construct is useful as an optimization. It turns out that
constructing a node for every chunk of whitespace in a document causes a
significant performance regression.
Conflicts:
src/compiler/build_tables/build_lex_table.cc
src/compiler/grammar.cc
src/runtime/parser.c
Now, grammars can handle whitespace by making it another ubiquitous
token, like comments.
For now, this has the side effect of whitespace being included in the
tree that precedes it. This was already an issue for other ubiquitous
tokens though, so it needs to be fixed anyway.
Now, you can't a particular occurrence of a symbol
in a grammar. You can only hide a symbol globally
(right now, by beginning its name with an underscore).
