make sure the total installation progress is always 100% (bnc#865585)

adjust the rounding issues when computing the subprogress percentages

- 3.1.77
Merge pull request #259 from yast/100_percent_progress

make sure the total installation progress is always 100% (bnc#865585)
NetworkService: handling of "no service running state". bnc878719
NetworkService: allow disabling network service completely
NetworkService: extended API - check for disabled service
Updated changelog
Merge pull request #260 from mchf/bnc878719

Improved handling of inactive network service state
fixed error message
package description
Merge pull request #261 from yast/review_140617_error_description

[Review] Request from 'schubi2' @ 'yast/yast-yast2/review_140617_error_description'