Merge pull request #4 from michaelavila/add_mit_license

Add MIT license
etl: allow other user-defined types for input

closes #5.
Merge pull request #6 from nathany/etl_type

etl: allow other user-defined types for input
Update readme
added hexadecimal test and example files
Merge pull request #7 from wvmitchell/master

added hexadecimal test and example files
rain drops exercise

PlingPlangPlong
Merge pull request #9 from nathany/raindrops

rain drops exercise
port grains exercise
Merge pull request #8 from nathany/grains
scrabble score exercise
Merge pull request #10 from nathany/scrabble-score

scrabble score exercise
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