This adds a new configuration option to Tiller to limit the number of
records stored per release.
Tiller stores historical release information (helm history, helm
rollback). This makes it possible to set a maximum number of versions
per release.
To enable this feature, use `helm init --history-max NNN`. Note that
because of the restrictions on Deployment objects, you will have to
re-install Tiller to add a limit.
Along the way, I found an unreported bug in the Memory storage driver.
This fixes that bug and adds substantially more tests to catch
regressions.
Closes#2332
Users can now specify a namespace filter for 'helm list'. Only the
releases within the specified namespace will be shown. For example,
'helm list --namespace foo' will only show releases for the 'foo'
namespace. Also added a namespace field to the table view.
Closes#1563