Merge tag '0.2.0' into develop

Release 0.2.0
only use/store values if needed
added README
getLists(): return Carbon object with Created date
documented getContextInfo() and getLists() methods
documented getListItemCount() and getListItems() methods
documented getListItem() and uploadListItem() methods
documented updateListItem(), deleteListItem(), getCurrentUserProfile() and getUserProfile() methods
added missing require vendor path
Merge branch 'feature/improvements' into develop
minor change in the Access Token explanation
added info about context token
remove warning
naming convention and other updates
updated copyright
minor corrections
minor corrections, take #2
Merge branch 'release/0.3.0'