Default to no root in AM::Serializers.

Every serializer in the app explicitly removed its root element anyway.
Remove ruby- prefix from .ruby-version.
Merge pull request #237 from CenturyLinkLabs/chore/nuke-prefix

Remove ruby- prefix from .ruby-version.
Merge pull request #236 from CenturyLinkLabs/chore/no-root-by-default

Default to no root in AM::Serializers.
Merge pull request #234 from CenturyLinkLabs/chore/webmock

Bring in webmock and bandaid some failures.
Fixing specs which were trying to make net calls