* combine permissions using logical operators `&` `|` and `~`
* removed unused command parameter from evaluation function
* hide commands from command list if the user has no permission to use them anyway
* generate info message if the user has permission for 0 commands
* added integrated permission handlers
* `PRIVATE_CHAT`
* `GROUP_CHAT`
* `USER_ID`
* `USER_NAME`
* `GROUP_CREATOR`
* `GROUP_ADMIN`