Fix sorting on peers table

[geftactics]

The peers list table has carets in the column headings, indicating that it should be possible to sort by those fields, which does not seem to be the case.

The PR enables sorting by clicking column heading, and defaults to most recent contacts at the top

Closes #146

[CLAassistant]

All committers have signed the CLA.

[davidlpower]

Hi @geftactics,

I checked out your code to test it out.

The sort is working but there is an edge case I wanted to bring up. I think you will need to update the table state to resort when the web client receives node information. To do that however there is a deeper problem. This table's rows can change dynamically so using index as a key can lead to issues with DOM updates and I think its also contributing to a bug which is messing with your sort.

[fifieldt]

I tested this patch on my node and it worked well.

It did require clicking the heading to re-sort when new data comes in, but it was still a better experience than no sorting at all :D