Update README.md

fixed typos
add table of contents to readme for easier browsing
Merge pull request #328 from uberspot/master

add table of contents to readme for easier browsing
Merge remote-tracking branch 'origin/dev'

Conflicts:
	README.md
refactoring
Update build config to simplify maven deployment.
fix for https://github.com/onepf/OpenIAB/issues/395
add logs
Merge pull request #397 from onepf/additional_logs

add logs
Fix crash with setupStateToString()
Update README.md
Possible fix for #406
Fix store search algorithm when no open appstores from availableStoreNames found on device.
Minor bugfix. local: availableStoreNames => preferredStoreNames
Fix https://github.com/onepf/OpenIAB/issues/401
Update gradle version.