Merge pull request #5 from exercism/travis-ci

add travis build for rust #4
Add MIT license
Merge pull request #6 from michaelavila/add_mit_license

Add MIT license
Update readme
Add problems file
Introduce proper config file
Delete outdated text config
Update config to ignore test directory
Add ignore property to config
Add deprecated section to config
Change name of key for consistency
Add foregone key to config
Add problems to config in semi-arbitrary order
Sanity check config in travis build