Add OctoLinker browser extension

[github.com/OctoLinker/browser-extension](https://github.com/OctoLinker/browser-extension)

Navigate through projects on GitHub.com efficiently with the OctoLinker browser extension.

Most projects consist of many files and third party dependencies. Files are referencing other files and / or dependencies by language specific statements like `import` or `require`. OctoLinker makes these references clickable. No more copy and search.

## Demo

![go](https://cloud.githubusercontent.com/assets/1393946/22407848/b89859ae-e66e-11e6-8ade-bb0e79def3ed.gif)

README.md

@@ -1299,6 +1299,7 @@ Go software and plugins.
 * [go-callvis](https://github.com/TrueFurby/go-callvis) - Visualize call graph of your Go program using dot format.
 * [go-pkg-complete](https://github.com/skelterjohn/go-pkg-complete) - Bash completion for go and wgo.
 * [go-swagger](https://github.com/go-swagger/go-swagger) - Swagger 2.0 implementation for go. Swagger is a simple yet powerful representation of your RESTful API.
+* [OctoLinker](https://github.com/OctoLinker/browser-extension) - Navigate through go files efficiently with the OctoLinker browser extension for GitHub.
 * [rts](https://github.com/galeone/rts) - RTS: response to struct. Generates Go structs from server responses.
 
 ## Software Packages