add fast decoding by using TextDecoder where available
add fast decoding by using TextDecoder where available

jutunen/jsPDF-table_2,ealves-pt/jsPDF,ealves-pt/jsPDF,JunichiWatanuki/jsPDF,SpatialVision/jsPDF,yWorks/jsPDF,yWorks/jsPDF,JunichiWatanuki/jsPDF,MrRio/jsPDF,jutunen/jsPDF-table_2,MrRio/jsPDF,SpatialVision/jsPDF,yWorks/jsPDF,ealves-pt/jsPDF,JunichiWatanuki/jsPDF,MrRio/jsPDF,JunichiWatanuki/jsPDF