Properly display piechart, first attempt

Should further address #312
Removed piechart, removed no shares notification

* Removed broken piechart for now
* Do not display message if no shares are found for calculations to
  avoid cross-tabe error messages

Fixes #312
Merge pull request #403 from TheSerapher/issue-312-piechart

Issue 312 piechart
Better number format for block percentages
Better number format for est. shares
Adding 3rd party Scrypt library

This will allow us to start checking a blockhash against a solution
submitted to the database.

Details on this in the ticket. Just a WIP to save file states.

Addresses #405
Adding more descriptive message for txfee

Fixes #400
Merge pull request #407 from TheSerapher/issue-400

Adding more descriptive message for txfee
Adding solution detections for blocks

This will finally fix all block finding issues with a 4 way detection.
The find upstream method will continue to try other ways to find a
proper share until they are all exhausted or a match was found.

* Use stratum solution, create scrypt hash from block header
* Use pushpoold solution, create solution string from block header
* Use first available upstream share in timerange of block time
* Use *any* first available valid share older than time of block

This will fix #405 - no more unknown blocks. Ever.
removing debug output
Adding share type to log output

This will display which detection mechanism caught the share.
Fixed stratum detection

Fixes #405
Added blockhash solution checking

Stratum of @moopless supports blockhash as a solution. Check for that
one first.

Addresses #405
fixing issue with upstream shares not being found
adding missing PHP closing tag
Allow guest access to pages with config options

This will allow pool owners to make certain pages public accessible
without user registration or login. Please check the config dist file
for details.

Fixes #408
Ensure people know what the memcache setting does

Even though memcache can be disabled, the memcache library is a
requirement as listed in the README.md. I clarified that in the
configuration file itself to ensure people install it even though they
might be disabling it for debugging purpose.

Fixes #409
Merge pull request #411 from TheSerapher/issue-405

Issue 405
Adding block height to blockupdate output

This should make tracing block updates easier.
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
Abort payout process if missing share_id

As discussed in #392 we should abort any payouts for rounds until the
issue is fixed.