`Rubocop` is now `RuboCop`

See https://github.com/bbatsov/rubocop/commit/ff167d8f202baf7a68955db0aaf0dc29afb7e7ee
Merge pull request #1295 from nevir/patch-1

`Rubocop` is now `RuboCop`
Add <head> to 404 so Livereload can add its script to the page
Update CHANGELOG
Add a protective require
Make option documentation consistent.
Test gzip extensions option.
Accept list of paths to exclude from gzipping.
Merge pull request #1268 from AndrewKvalheim/gzip-ignore

Excluding paths from gzipping
Merge branch 'v3-stable'

Conflicts:
	middleman-core/lib/middleman-more/extensions/asset_hash.rb
Munge build path so that path_match works against it in gzip extension
Remove options to proxy or ignore through `page`, and use Middleman::Util#path_match for matchers to allow a wider set of matchers.
Update CHANGELOG to mention proxy and ignore are gone from page
Merge pull request #1308 from bhollis/slim_page

Remove options to proxy or ignore through `page`
Update listen gem
Merge pull request #1309 from Arcovion/patch-1

Update listen gem
listen gem conflict
rubocoping
Update listen code
Merge pull request #1310 from Arcovion/patch-1

Update listen code