* refactor: Centralize MIB include directory specification
The default is now:
```
$config['mib_dir'].'/mibdirname:'.$config['mib_dir']
```
This means we exclude OS mibs and only use ours (we could prepend `+` if we want to include os mibs.
All snmp calls should only include the name of the subdirectory under the mibs directory.
* Remove d_echo from Proc
Fix snmpsim tests.
More mibs needed from http://www.ieee802.org/1/files/public/MIBs/
Updated mib names
Updated poller function and siklu call
Updates for Siklu detection
Removed one graph not supported
Added rfOperationalFrequency graph
Removed modulation graph
Work on siklu support
Siklu packets supports
Last updates for Siklu support
Updated more siklu support
Tony Murray
Thom Seddon
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