Merge pull request #1 from slav/master

latest updates #1
Merge pull request #2 from slav/master

 pull request #2 from slav/master
async and regular methods for labels update and delete
Merge remote-tracking branch 'origin/master' into LabelUpdates
list of skus has been splitted to the pages
Update labels - check for the labels to update count
removed unnecessary part of method comments
Merge pull request #2 from DmytroSV/master

update inventory API to have an ability to update labels