Merge tag 'v0.3' into develop

Release v0.3 for RethinkDB v1.13. Fixes #91
Fixed token not in stream cache error
Tidied up result loading code
Continue and stop queries now use the same connection as the start query.
Fixed cursors for FEED queries being deleted
Protected a number of critical section in `Session`
Merge branch 'feature/issue_103' into develop
Fixed issue with cursor not properly checking errors
Fixed race condition with cursors
Fixed another deadlock and an issue which caused connecions to be closed early
Changed Exec to not use NoReply and instead close the cursor immediately
Merge branch 'feature/issue_103' into develop
Bumped version number and updated change log
Merge branch 'release/v0.3.1'