adblock: update to 1.5.1

adblock: update to 1.5.1

Apply adblock updates 1.4.10-1.5.1

Signed-off-by: Hannu Nyman <hannu.nyman@iki.fi>
Original commit messages:

adblock: update 1.4.10
- add 'enabled' check to iface hotplug event handler
- decrease startup priority from 99 to 90
- fix tab indentation in config

adblock: update 1.5.0
* add new 'envchk'function to check adblock environment only,
  i.e. check volatile firewall rules or uhttpd instances
  without list updates
* add new optional parm 'adb_loglevel',
  set it to "0" to mute output (print only errors)
* set hotplug priority to '90' as well (missed in the last commit)
* documentation update
* cosmetics

adblock: bugfix 1.5.1
* fix uhttpd detection in tcp 4+6 configurations