In Section 2.0, updated formatting for proper bullets.
Copy changes in section 2.0

These are copy edits to make the explanation of the role of the xAPI a
bit more targeted.
line length
Merge pull request #1 from bscSCORM/silvers

line length / spacing
Merge pull request #162 from aaronesilvers/master

Section 2.0, updated formatting for proper bullets and copy changes