Add loggingMode to the mercury constructor

[MulverineX]

• Add efficient shim to print binding
• print mode; default/current behavior.
• Add receive mode; non-blocking event listener to receive log items, does not tamper with log contents.
• Add modify mode; blocking callback that allows for modification of log items before printing to actual.
• Add replace mode; blocking callback that receives log items and cancels printing to log.