Ip plugin: save IP for specified amount of time

[okin]

Running this on my desktop machine makes me think that it would be nice if the IP plugin did some caching of the current IP for a specified amount of time as my IP hardly ever changes.
And if the network in general fails I will surely notice otherwise ;)

[fleaz]

I had the idea of adding a "caching" feature for every plugin so we can reduce system load. +1 for this idea :)

[okin]

Easy way could be the use of functools.lru_cache.