Adding doc system to build. Updated docs, fixed links.

mkdocs.yml

@@ -0,0 +1,11 @@
+site_name: Mattermost Documentation
+site_url: http://docs.mattermost.org
+repo_url: https://github.com/mattermost/platform
+repo_name: GitHub
+site_favicon: favicon.ico
+copyright: "Copyright (c) 2015 Spinpunch, Inc. All Rights Reserved."
+strict: true
+docs_dir: doc
+site_dir: documentation-html
+use_directory_urls: false
+theme: mkdocs