Cleanup modelCourse achievements.

[somiaj]

Cleanup and update the default achievements in the modelCourse.

• Remove the same comment from the bottom of all evaluators. This is hard to maintain, instead put all the information in achievements_readme.txt and point to this file from other evaluators.

• Cleanup the achievement evaluators:

  • Simplify the code, don't use else statements when there was a return inside the previous if. Clean up some of the logic.
  • Take advantage of the new $globalData->{completedSets} hash to avoid looping through all problems to determine if a set is completed.
  • Ran perltidy on them using an 80 character limit.

• Remove some evaluator duplication. The complete n problems or n sets can all be done using a single evaluator, since the only difference is the $maxCounter setting from the achievement.

• Remove all unused achievement evaluators. There are lots of these that are really just the same example achievement over and over again to see if particular problems from particular sets were completed. The images are still available for helping people think of names, but the evaluators don't need to be included. Instead provide four example evaluators for completing specific problems and/or sets.

I still need to do a bit of testing on this, so making this a draft, but sharing so others can help test/give feedback.