Display network hashrate in public API
Display network hashrate in public API

Instead of 0 show the actual hashrate, still shows 0 if unable to
connect to RPC server.

Fixes #511

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