Hotfix v2021.07.05-5

Hotfix v2021.07.05-4-otterscan

Hotfix release v2021.07.05-3-otterscan

Release v2021.07.05-2-otterscan

Add explicit checkout of tags to README

For some reason the instructions did NOT work for me, the only way I was able to get the tags to be able to check them out was to run `git fetch otterscan --tags` so I suggest that it be added here 

Make use of ots_getBlockDetails on tx details to save traffic when calculating block tx count (because of tx idx position)