Use unix epoch for Graphite from/to for absolute time ranges

[torkelo]

So it has come to my attention (thx @brutasse) that Graphite support unix epoch seconds as from/to parameters. This is not mentioned in the api docs.

It seems to be supported in Graphite pre 0.9.10 so it is not a new feature.

I will commit this change to master. People who have used the timezoneOffset please test this against master if you have time. timezoneOffset is not used anymore so it should not matter if this is set in config.js.

I have tried myself to change my local computer timezone and absolute time ranges (zoom) seems to work fine.

[brutasse]

👍