fix(helm): fix linter test panic

Handle a previously unhandled error in the linter. This simply bails out
if a chart's values files do not parse.

Also, changed the implementation of CoalesceValues to return a map even
on error.

Support Linter for Values namespace

fix(chartutil): Ensure ReadValues doesn't return a nil map

fix(lint): Return non-zero exit status when lint errors present

feat(tiller): add .Template object in templates

chore(docs): update "Name" field in values.yaml

feat(lint): lint an archived chart

fix(cmd): remove --file flag for helm get

fix(*): fix various style issues from make test-style

Users can redirect stdout to a file

* the template refers to .Values.Name but the
values.yaml file has a name field with a lowercase
"n". Figured changing this is the right move since
yaml is case sensitive.

* part of #836

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

fix(helm): show correct filename on error

Closes #847.

Closes #895

feat(cmd): silence usage on error

Closes https://github.com/kubernetes/helm/issues/864

fix(chartutil): fix chartutil.Expand function