Handling :abort button + unified setting up the UI

- bnc#886662
New version and changes file entry
Merge pull request #221 from kobliha/ConfirmAbort-Unification

Asking user for confirmation while aborting the installation
retranslate release notes button when going back in workflow (bnc#886660)
Merge pull request #222 from jsrain/master

retranslate release notes button when going back in workflow (bnc#886660)
fix proxy option passing from linuxrc to yast

linuxrc already provides proxy settings in URL form. Use it.
release 3.1.101
set the correct display-manager
workaround for bugge plymouth
docu added
packaging
Merge pull request #224 from yast/review_140721_start_second_boot

[Review] Request from 'schubi2' @ 'yast/yast-installation/review_140721_start_second_boot'
Merge branch 'master' into proxy

Conflicts:
	package/yast2-installation.changes
	package/yast2-installation.spec
Merge pull request #223 from yast/proxy

Proxy
- do not log sensitive information in y2start.log (bnc#888645)
Merge pull request #225 from aschnell/master

- do not log sensitive information in y2start.log (bnc#888645)
do not repeat release notes downloading on network time out (bnc#885486)

- 3.1.105
Merge pull request #226 from yast/network_timeouts

do not repeat release notes downloading on network time out (bnc#885486)
use short product name for the default base product release notes (bnc#885247)

(the default is read from the installation medium)
display at least an empty dialog when downloading release notes (bnc#889196)

to hide the previous dialog in the installation workflow