add 404 page, remove old license links

fabfile.py

@@ -70,6 +70,7 @@ def web():
     with virtualenv(VENV_DIR):
         local('./website/create_code_samples spacy/tests/website/ website/src/code/')
 
+    jade('404.jade', '')
     jade('home/index.jade', '')
     jade('docs/index.jade', 'docs/')
     jade('blog/index.jade', 'blog/')

website/src/jade/blog/introducing-spacy/index.jade

@@ -19,4 +19,4 @@ include ./meta.jade
             +TweetThis("Computers don't understand text. This is unfortunate, because that's what the web is mostly made of.", Meta.url)
 
         p If none of that made any sense to you, here's the gist of it.  Computers don't understand text.  This is unfortunate, because that's what the web almost entirely consists of.  We want to recommend people text based on other text they liked.  We want to shorten text to display it on a mobile screen.  We want to aggregate it, link it, filter it, categorise it, generate it and correct it.  
-        p spaCy provides a library of utility functions that help programmers build such products.  It's commercial open source software: you can either use it under the AGPL, or you can  #[a(href="/license") buy a commercial license] under generous terms.
+        p spaCy provides a library of utility functions that help programmers build such products.  It's commercial open source software: you can either use it under the AGPL, or you can buy a commercial license under generous terms.

website/src/jade/header.jade

@@ -115,7 +115,6 @@ mixin WritePage(Site, Author, Page)
                 li(class={active: Page.active.home}): a(href="/") Home
                 li(class={active: Page.active.docs}): a(href="/docs") Docs
                 li: a(href="http://api.spacy.io/displacy", target="_blank") Demo
-                //li(class={active: Page.active.license}): a(href="/license") License
                 li(class={active: Page.active.blog}): a(href="/blog") Blog
             main#content
                 block

website/src/jade/tutorials/add-a-language/index.jade

@@ -117,8 +117,8 @@ include ./meta.jade
         
     details: summary: h4 Create frequencies
         pre.language-bash: code
-            $ python bin/get_freqs.py
-            $ python bin/gather_freqs.py
+            | $ python bin/get_freqs.py
+            | $ python bin/gather_freqs.py
 
     details: summary: h4 Brown clusters