- Added tests for using a function inside a template that is evaluated using the "tpl" function

Implementation for #1978

Adds the `required` function in enginge.go to support required
properties in values.yml. When a chart developer wishes to specify
intent in requiring a value, they can use this function to declare
an error message that gets returned when chart rendering fails
when a required value is not present in values.yml.

Closes #1580

This adds the {{.Capabilities}} object to the template variables so that
chart authors can write charts that are aware of teh Kubernetes
capabilities of the current cluster.

Closes #1608

This adds a fromYaml template function.

Closes #1604

This adds a function engine.FuncMap that returns a function mapping that
better represents the functions passed to a template. The linting logic
is reconfigured to use this function instead of the sprig.FuncMap
function.

Closes #1366

This adds the function toYaml to the Engine template functions.

Closes #1225

Closes #1076

This changes "pkg/chartutil".Files.Get to return a string, removes
"pkg/chartutil".Files.GetString, and adds
"pkg/chartutil".Files.GetBytes.

Closes #1020

This adds a context-aware template function called 'partial' that will
allow rendering other templates in a chart into a string value, which
can then be piped to other functions. Usage is something like
'{{partial 'path/to/template.yaml' | indent 2}}'

This might be a bad idea.

Closes #1005

Templates can now access the non-template files in a chart by using
the '{{.Files}}' map inside of a template.

Relates to #950

This fixes a bug in which passed-in values files were not correctly
merged into the chart's default values YAML data. I believe it also
fixes some other prioritization bugs in values merging.

The existing unit test was wrong (see TestCoalesceValues). It is
fixed now. Also added more tests to simulate issue #971.

In the course of writing this, I removed some vestigial code as
mentioned in #920.

Closes #971
Closes #920

https://golang.org/doc/go1.4#canonicalimports

Template paths were relative to the chart that contained them, which
meant that all templates were named 'template/SOMETHING'. This made it
trivially easy to hit namespace collisions as in #933.

Template path names are essentially opaque strings so this patch simply
changes them to be qualified by parent chart.

This allows templates to access information about the template file.
Right now, the template can only access the .Template.Name, which is the
chart-relative path to the current template.

Closes #894

Instead of printing "no value", this prints an empty string by
default, but adds a Strict flag on the engine, which (if true)
will cause a template render to error out if a value is not supplied.

Strict is set to false so that developers can instead use `default` to
set default values.

This adds the .Values namespace qualifier to all values

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.

Fixes: https://github.com/kubernetes/helm/issues/803

This commit finally ties `helm install` together with the Kubernetes
client library to make an end-to-end trip.

There were several small fixes to go on both client and server side,
along with some changes to proto to support better error reporting.

The alpine chart has been updated to exhibit how the new Helm works.