[CMDMANAGER] implement !cmdgrant and !cmdrevoke: manage command priviledges per client
This implements #215
[TESTS] added test cases for !cmdgrant and !cmdrevoke
[CMDMANAGER] added command !cmduse + improved !cmdgrant and !cmdrevoke
Merge pull request #217 from FenixXx/release-1.10

[CMDMANAGER] implemented !cmdgrant and !cmdrevoke