Stat management

[MaynardMiner]

Because a good amount of users work from USB- Reducing as many read / writes is always favorable.

This proposal aims to do the following:

1.) Stats are pulled at the start of SWARM from stats folder.
2.) Stat table will be edited while SWARM is running, and the stats time periods will stored on the $stats variable.
3.) $stats will be written to filed when appended. This will now only be the only time SWARM writes the file.

This will multiply the stat variable exponentially, but I imagine overall the size will not have an impact on the running of SWARM and its overall memory use.

Furthermore, I plan to use dynamic arrays to improve the speed, as it seemed to greatly improve the speed of loading of miners and pools in linux.