Added go trie example with tests en 2 benchmarks

I implemented the Trie in Go, with running tests and bencharks for Insert and AutoComplete.

Implementation goes:

````go
    t := trie.NewTrie()
    t.Insert("lorem")
    t.Insert("ipsum")
    t.Insert("dolor")
    t.Insert("sit")
    t.Insert("amet")
    t.Insert("consectetur")
    t.Insert("adipiscing")
    t.Insert("elit")

    // Should return []string{"amet", "adipiscing"}
    results := t.AutoComplete("a")
````