Merge pull request #836 from andrzej-jankowski/prescan_fixes

Scan - prescan fixes
Scan - special queue for ui calls added
typo
CHANGES.rst
settings fix
Merge pull request #837 from andrzej-jankowski/scan_improvements

Scan improvements
Merge pull request #838 from andrzej-jankowski/develop

settings fix
fix
Merge pull request #839 from andrzej-jankowski/autoscan_fix

Better errors handling
Merge remote-tracking branch 'allegro/v2.0.0-rc3' into develop
Merge remote-tracking branch 'allegro/develop' into develop
ssh_cisco_catalyst fix
tests fix
Merge pull request #840 from andrzej-jankowski/develop

Scan - ssh_cisco_catalyst fix
beeter Thomas-Krenn detection
Merge pull request #841 from andrzej-jankowski/develop

Better Thomas-Krenn detection
version 2.0.0-rc4
Update .travis.yml
serial numbers validation added
fix picle errors