Minor cleanup

Renamed some variables, moved poll code into separate function
startPoll, reordered some declarations
Converted to IIFE
Enable unwrapDescendants

Because unwrapDescendants now uses a max iterations guard, there is less
of a performance risk so it can be re-enabled here
Use an IIFE and other misc improvements

Changed to use an IIFE. Cleaned up comments, added comments. Created
remove function to avoid some DRY violations. Created some common
variables like forEach within the IIFE. canonicalizeWhitespace now does
more explicit replacements. Created some non-inlined functions for basic
clarity and to reveal a common targeted removal pattern. Other misc
minor changes.
Added a comment about collectTextNodeLengths

Also added some blacklisted axes