Merge branch 'release/v0.8.1' into develop
Bump missed version number in package.json
First pass at implementing Session#authorise retries.

Not yet tested against live API. Issue #11.
Add retry interval options
Deprecated LastFmSession.authorise()

Supplying a token value in the options will automatically
attempt to authorise it.
Add LastFmSession.cancel()
Fixed bug where isAuthorised() was not returning boolean.
Merge branch 'feature/reuseable-session-auth' into develop
Merge branch 'hotfix/v0.8.3' into develop

Conflicts:
	History.md
	package.json
Merge branch 'hotfix/v0.8.4' into develop

Conflicts:
	History.md
Bumping version numbers.
Merge branch 'release/v0.9.0'