initial attempt for generic proposal client
add finish client
add test for proposal client
add test for finish_client and also fix founded bugs
release
allow execution of tests
use proper script to run test
add logging how clients are called
add auto client
add forgotten methods for modified flag
copy doc about proposal API
add doc to finish client
move API description to methods
remove forgotten headline
Proofreading: English, more YARD-like output, fit in 80 columns

For reviewing, use also

    git diff --color-words
use better argument type
Merge branch 'installation_clients' of github.com:yast/yast-yast2 into installation_clients
Merge remote-tracking branch 'origin/master' into installation_clients

Conflicts:
	package/yast2.changes
remove unused method
auto_client: proofread, purpose and types better documented.