oceani: change labels to look like enum values, not variables.

A label now looks like ".foo".  This makes it a completely separate
namespace from variables.

When we introduce enums, the values will also look like ".foo" an we
know which enum is intended based on context.
Each switch/while will potentially create a local enum type for the
labels.

Signed-off-by: NeilBrown <neil@brown.name>