Add basic contributing guidelines
Add word on travis
Rework project layout to separate lib

- Library moves to lib
- Executable hammertime now really depends on lib (lib is not
  recompiled)
Merge remote-tracking branch 'upstream/sprint' into new-layout
Add reports to lib
Modularized tests
Move Storage.File to lib
Tests for cliParserInfo
First version of the CLI parser
Parse CLI
Fix test name
CLI parser: fixed optional timespan + ReportType parsing
Refine parser (header, completion, …)
Update CONTRIBUTING.md

Wrap text at 80
Merge remote-tracking branch 'origin/contributing' into sprint
Merge optparse-applicative into new-layout