clarify what "dependencies" are.

One could think these are composer dependencies and run the install
subcommand of Composer, which will inevitably fail because of virtual
packages. This might change if Composer improves in the future.
Explain the composer.json change

Giving a clear explanation about this change and instruction will avoid
unwanted composer.json commits.
run php-cs-fixer on the UnitOfWork file

I'm going to change this file, I prefer to fix CS issues before doing
anything.
Merge pull request #510 from greg0ire/typo

fix 2 typos in the same word
Merge pull request #509 from greg0ire/contributing

Contributing
remove check for full versioning

This check was introduced in 42ae30c, but we are unable to figure
out why. If there was a rationale behind this, the best way to
figure it out is to revert the change and see if anything wrong happens.
This checked prevented the use of UnitOfWork::check* methods with simple
versioning.
Merge pull request #511 from greg0ire/simple_versioning_is_not_dead

Resurrect simple versioning
test that the versionname value is set properly