Skip proof-of-stake blocks in findblock cron
Skip proof-of-stake blocks in findblock cron

* Do not add proof-of-stake blocks to database

Fixes #569

sasselin/xcoin-mpos,mculp/chunky-mpos,evgenyponomarev/pool,shreeneve/test,sixxkilur/php-mpos,machinecoin-project/php-mpos,ychaim/php-mpos,ychaim/php-mpos,xisi/php-mpos,CoinHashMe/MPOS-SSO,shreeneve/test,mculp/chunky-mpos,machinecoin-project/php-mpos,nimblecoin/web,evgenyponomarev/pool,bankonme/php-mpos,mculp/chunky-mpos,bankonme/php-mpos,MPOS/php-mpos,CoinHashMe/MPOS-SSO,BlueDragon747/php-mpos,mculp/chunky-mpos,evgenyponomarev/pool,mmitech/php-mpos,studio666/php-mpos,machinecoin-project/php-mpos,UNOMP/chunky-mpos,UNOMP/chunky-mpos,nimblecoin/web,BlueDragon747/php-mpos,CoinHashMe/MPOS-SSO,nimblecoin/web,sasselin/xcoin-mpos,ychaim/php-mpos,MPOS/php-mpos,shreeneve/test,xisi/php-mpos,studio666/php-mpos,bankonme/php-mpos,UNOMP/chunky-mpos,UNOMP/chunky-mpos,CoinHashMe/MPOS-SSO,studio666/php-mpos,mmitech/php-mpos,mmitech/php-mpos,sasselin/xcoin-mpos,MPOS/php-mpos,sixxkilur/php-mpos,CoinHashMe/MPOS-SSO,BlueDragon747/php-mpos,sixxkilur/php-mpos,xisi/php-mpos