New properties are available to template developers.

Closes #1554

This adds support for packs, pre-configured chart patterns that can be
used to quickly create a custom layout for your new chart.

This refreshes docs, as discussed in #719, and adds a few new sections
to the docs.

Closes #719

This causes 'helm dep [up|install]' to ignore files in charts/ that
start with either a dot or an underscore. It also changes the
chartloader to ignore those files.

Also, if a 'helm dep up' does not find a charts/ directory, it creates
one.

Closes #1342

After #1021 ` .Files.GetString` does not exist any more.

The name for the default values file is `values.yaml` and not `.values.yaml`.

Closes #1241

Closes #1034

This encourages people from making container names depend on release
names.

This explains how a hook resource is not managed as part of the release
lifecycle.

Closes #960

Closes #938

…since people might not be familiar with Go templates.

This provides support for "global" variables. It does this by
declaring "global" to be a special namespace. It then copies this
namespace into every subchart, coalescing it into any "global"
namespace found there.

The net result is that if "global.foo" is set in the YAML file, it
will be available to every chart/subchart as ".global.foo" regardless of
where that chart is in the subchart tree.

Closes #797

Updated the link which was dead pointing to `https://github.com/deis/charts`

Also noticed a field was omitted from metadata.proto and the docs.
Added it back, though functionally it is a no-op.

Make sure all fields are marked optional or required in the doc.