First working version of PPLNS payouts

* Based PPLNS on Prop Payout script
* Using defaults from prop payout, no class adjustments
* Added more methods required for PPLNS
* Added block methods for dynamic payout calculations
* Added PPLNS Sidebar that also displays the PPLNS Target
 * Shares beyond this target will not be included in payouts
 * Shares missing to this target will be added from archives
* Enabled archiving by default for PPLNS
* Added configuration options for PPLNS
 * Documented the usage for PPLNS, defaults are sane
* Added pplns_payout to run-crons

Addresses #143 and if accepted will fix it
Fixing dynamic calculations
Bail if no shares found in proportional payout
adding debug switch to crons
Fix issue with shares not being found in archive

* Used wrong ID field to find shares
* Added debug command line switch, added some output to PPLNS payout

Addresses #143