Merge pull request #10 from adlnet/master

update garemoko master to adlnet
Merge pull request #11 from adlnet/master

update garemoko master to adlnet
Added definition of activity

Solves https://github.com/adlnet/xAPI-Spec/issues/24
fixed tabbing properly
Merge pull request #65 from garemoko/activityDefinition

Activity definition