Refactor message to fix misspell finding

Refactor message of diff matcher to get rid of misspell finding.

Fix dash quotation issue

Ref: #342

Make sure to quote if string is just a dash by updating the neat version.

Use Ginkgo version from modules

Use `go run` for Ginkgo to exactly run the expected module version.

Add test case where from or to is null

Add test case to check branch that deals with changes where one of the
from or to item is null.

Bump to neat release `v1.3.12`

Fixes #309

Remove `snap` target for now

It makes more trouble than it is useful at the moment. Removing support for `snap`.

Introduce `--additional-identifier` flag

Add flag to `between` command to specified an additional custom
identifier for the named-entry list processing.

Create defaults section for report flag values

Create single place to define defaults for report option command line flags
to fix inconsistency of the usage of defaults between using `dyff` as a binary
versus using the `dyff` code in a test case.

Fix broken test case

With the unified text rendering, the unchanged output is not also
colored line by line rather than coloring the line feed character as
part of one big color format. Therefore the expected test output is
looking slightly different in raw mode.

Omit empty documents in Kubernetes compare

When comparing multi document files using Kubernetes semantics, omit empty
documents in the list of documents to compare.