Rename to cfenv and environments

This change renames the files in the project to adhere to the cfenv
naming convention.  In addition, it changes file name references of
versions to environments.
cfenv-environment-file

This change fixes cfenv-environment-file.
cfenv-environment-origin

This change fixes cfenv-environment-origin.
cfenv-environment-file-read

This change fixes cfenv-environment-file-read.
cfenv-environment-name

This change fixes cfenv-environment-name.
cfenv-environment

This change fixes cfenv-environment.
cfenv---version

This change fixes cfenv---version.
cfenv-help

This change fixes cfenv-help.
cfenv-completions

This change fixes cfenv-completions.
cfenv-hooks

This change fixes cfenv-hooks.
cfenv-environments

This change fixes cfenv-environments.
cfenv-prefix

This change fixes cfenv-prefix.
cfenv-whence

This change fixes cfenv-whence.
cfenv-which

This change fixes cfenv-which.
cfenv-shims

This change fixes cfenv-shims.
cfenv-sh-rehash

This change fixes cfenv-sh-rehash.
cfenv-rehash

This change fixes cfenv-rehash.
cfenv-root

This change fixes cfenv-root.
cfenv-environment-file-write

This change fixes cfenv-environment-file-write.
cfenv-local

This change fixes cfenv-local.