Determine authentication errors in CLI init
Conform astakos-CLI commands to kamaki standards

Fixes #22
Enrich CLI errors in "cmds.cyclades"

Refs #21
Enrich CLI errors in "cmds.image"

Refs #21
Enrich CLI errors in "cmds.network"

Refs #21
Enrich CLI errors in "cmds.pithos"
Error decorators preserve decorated method names
Manage project_id errors in all API commands

Fixes #21