Add accumulated miner share column

[Sword-Smith]

A column for accumulated mining share is added on screens with a width over 640px.

This closes #63.

[hsjoberg]

Thank you for your well made pull request @Sword-Smith!

I am not sure I agree with adding this column however, sorry. My biggest concern is keeping the table simple.
I have added "Potential share" to the miners page, which would count the hashrate of all pools that have signaled at least once. Does this satisfy what you're trying to accomplish?

Cheers
Hampus

[Sword-Smith]

I see your point. I was thinking this extra column would make it easier to conclude something along the lines with "we only need to convince these three mining pools to get our proposal through".

[Sword-Smith]

But obviously your call. Add it if you think it is useful, don't if you don't. Furthermore a slight modification to the presentation of this number would probably be desired now that you have added sorting options for each column.