Remove support coffeescript

This is no longer used since #298

.codeclimate.yml

@@ -1,14 +1,11 @@
 engines:
   bundler-audit:
     enabled: true
-  coffeelint:
-    enabled: true
   duplication:
     enabled: true
     config:
       languages:
       - ruby:
-      - coffeescript:
   eslint:
     enabled: true
   fixme:

Gemfile

@@ -2,8 +2,7 @@
 source 'https://rubygems.org'
 
 gem 'nanoc'
-# General filtering
-gem 'coffee-script'
+
 gem 'icalendar' # ical files
 gem 'kramdown'
 gem 'sassc'

Gemfile.lock

@@ -9,10 +9,6 @@ GEM
       execjs
     builder (3.2.3)
     coderay (1.1.2)
-    coffee-script (2.4.1)
-      coffee-script-source
-      execjs
-    coffee-script-source (1.12.2)
     colored (1.2)
     concurrent-ruby (1.1.5)
     cri (2.15.9)
@@ -136,7 +132,6 @@ DEPENDENCIES
   adsf
   autoprefixer-rails
   builder
-  coffee-script
   guard-nanoc
   highline
   htmlcompressor

Rules

@@ -174,12 +174,6 @@ end
 #
 # ASSETS
 #
-compile '/assets/scripts/**/*.coffee' do
-  filter :coffeescript
-  filter :uglify_js if production?
-  write ext: 'js'
-end
-
 compile '/assets/scripts/**/*.js' do
   filter :uglify_js, harmony: true if production?
 end