v1.6.4 update: Intro sequence, pre/post-test, tutorial sequence

Main updates in v1.6.4:

 Intro sequence: game opens up with intro sequence setting the scene before character selection

 Pre/post-test: functionality now present for storing pretest/posttest assessments, but pretest is turned off for now

Tutorial sequence: player now goes through a tutorial demonstration, where Dr. Phrasier demonstrates how to adjust punctuation to complete the first level.