Add spec helper and prepare mutant
Sync devtools
Fix YARD documentation for Collection

This is the first pass for an example dm2 style refactoring.
Yardstick does not detect any problems on this class anymore.
Add style issues file
Change Collection codinng style to dm2 conventions

* Use parantheses
* Do not use 1.9 syntax
* Use single quotes for non interpolated string literals
* Do not use redundant begin rescue blocks
Remove fixed style issue notes
Return self for command methods on collection
Update style issues
Use single word variable names where possible

And favor Hash#fetch() over Hash#[] where the existance of keys is prior
knowlege.
Update style-issues
Do not document classes with "Represent $foo"

All classes represent something so using "Represent" in a class
description is redundant.
Rename Collection#name= to Collection#rename

* Cleanup CQS role
* Update style issues
Rename Collection#[] to Collection#fetch

* Far more in line with Hash#fetch vs Hash#[]
Rename Collection#[]= to Collection#replace

* Also update style issues
Replace magic values with constants
Remove Collection#<<

Do not provide Array#<< like method with inconsistend behavior