Moves symbolise to meta where shared by asset and batch

Closes #26
Patch release 2.1.2
Toggle stack-trace

Closes #27
Patch release 2.1.3
Update README

Closes #29
Remove Multi

Closes #30, Resolves #15
Major Release 3.0.0
Improved docs around UrlGenerator (HTTP LS)

Closes #32, Resolves #28
Adds correct keys in config example

Resolves #33
Exception thrown when using NullClient triggering additional unnecessary dynamo calls

Closes #34
Patch release 3.0.1
Custom Metrics

Closes #35
Minor Release 3.1.0
Use correct opt hash

Closes #36
Patch release 3.1.1
Initial work on cache class and load strategy