Started migrating the tests from issue into workpackage #1754

Starting with the validations, we're moving everything out of issue into
workpackage: Accompanying this, the tests are migrated into specs. This
branch concentrates on moving the validations.

  * added shoulda for simplified testing of validations
  * added date_validator to simplify&fix date-validation
  * moved the basic-validations (presence_of, date-validations) into the workpackage_basics_spec.rb
Adding the more complex validations (re-/scheduling, versions etc.)

Also pulled up lots of methods from issue, that are now grouped in
various concerns under models/work_package: This is just a test to see
how much travis/ci likes this, for now it is only an organizational
means to work on the transition without interrupting the
work-package-core too much.
fixing specs: getting validations for workpackages in the workflow-specs to run
fixed specs for the planning-elements
Add numbered headings documentation to detailed wiki syntax description
Started migrating the tests from issue into workpackage #1754

Starting with the validations, we're moving everything out of issue into
workpackage: Accompanying this, the tests are migrated into specs. This
branch concentrates on moving the validations.

  * added shoulda for simplified testing of validations
  * added date_validator to simplify&fix date-validation
  * moved the basic-validations (presence_of, date-validations) into the workpackage_basics_spec.rb
Adding the more complex validations (re-/scheduling, versions etc.)

Also pulled up lots of methods from issue, that are now grouped in
various concerns under models/work_package: This is just a test to see
how much travis/ci likes this, for now it is only an organizational
means to work on the transition without interrupting the
work-package-core too much.
fixing specs: getting validations for workpackages in the workflow-specs to run
fixed specs for the planning-elements
pulled up changes to the scheduling-rules into the module.
rebased&merged changes
Merge pull request #381 from opf/feature/numbered_headings_documentation

Add numbered headings documentation to detailed wiki syntax description
Fixes WP description diff view
Adds changelog entry
Migrate unit tests to rspec (to be able to disable them in self-registration per mail).
re-merged the changes from the unit-tests-branch&fixed the tests.
Stubb settings values in spec instead of persisting them.
query returns all work packages
initial work_package#index implementation

Only implements index within projects for now
lets query saving redirect back to work_packages controller