guard: add Guardfile
appveyor: add appveyor.yml
travis: enable cache (on travis.com)
rubygems: move all development_dependencies => Gemfile
RSpec: change spec dir structures
RSpec: use cgi / webmock to test registry_client
registry_client: add RegistryClient class

* add get_repositories()
* add get_dependencies()
repository: fix clone() to load snippet.json
repository_manager: add install_repository()
command_line: add Sspm classes

* add sspm-install sub-command
* add sspm-search sub-command
command_line: add tests for Command class
command_line: sspm: add tests for calling sub_command
command_line: sspm-install: add tests to install repository
command_line: sspm-search: add tests for find repository
bin: add sspm command