Allow mipmap's as icon

[wendt88]

It would be nice to use mipmap's as notification icon like the new launcher icon

for example add this snippet here:

let defType = 'drawable';
let segments = resourcename.split('/');
if (segments.length > 1) {
    defType = segments[0];
    resourcename= segments[1];
}

so as icon property could be set: mipmap/icon or icon (to get it from drawable)