Only reverse top-level repeater matches

When matching on lookbehind, repeater vars go in reversed, which we have
to correct. Previously it was doing it for all `level: 1` matches, but
what we actually need is to do it for `topLevel` patterns. This adds
a `topLevel` key to match objects so we can make the distinction.
Allow infix matching when building ObjectGet terms
build
Merge branch 'pr/199'
build
support for template strings #153
build
Merge branch 'gh-pages'
support for yield expressions #190
build
create a new pattern literal #192
build
using unmagnified version of escodegen #138

jsc doesn’t like the minified output of escodegen so until they fix
just use the unminified version
should be using tolerant errors #190
condition for multi token macro names #200
handle whitespace in multi token macro names #200
build
checking before exposing #191
correcting name in error message #191
More compiler options

Use `--ast` to print the expanded AST. Use `--format-indent=NUM` to set
how many spaces to use for indentation. Use `--better-hygiene` for an
experimental compiler pass to remove hygiene tags where possible.