code: function writeWallet( path, keys ){
   	var data = "";
   	for( var i=0; i<keys.length; i++ ){
   		var key = keys[i];
  		if( i > 0 ) data += "\n";
   		data += key.wifC+"	"+key.label;
   	}
   	try{
   		FS.writeFileSync( path, data, { encoding: "utf8", mode: 0600 } );
   	}
   	catch(err){
  		throw new Err.FileSystemError(err); 
   	}
   }
docs: /*
  writeWallet
  
  Internal function to write the given array of KeyPair objects to the given path