Add Travis testing
Merge pull request #12 from sjakobi/travis

Add Travis testing
Add Travis status badge to README.md
Merge pull request #13 from sjakobi/patch-1

Add Travis status badge to README.md
Complete EXERCISES.txt

The hexadecimal and binary-search-tree weren't included in the EXERCISES.txt file and therefore weren't automatically fetched by the CLI.
Rename binary_search_tree.go to example.go
Merge pull request #14 from sjakobi/patch-2

Complete EXERCISES.txt
Merge pull request #15 from sjakobi/patch-3

Rename binary_search_tree.go to example.go