device manager panic problem

[vuichka]

I am using your lib and I am satisfied with your impl of device manager but
it panics no matter what on line :160 device/manager.go
My proposal is to add make() on NewManager or to fix line :160 with map init

Also Its not naive at all that you should call .Devices() and .Controllers() till you can use devices manager so thats +1 for 1st approach with maps initialisation

[diamondburned]

admittedly this library is not very well-written due to my lack of understanding with the intiface API. honestly, i wasn't expecting people to be using this at all!

i'll be rewriting this library as a v2 to address these issues