Fix #2272,#2232,#2336 (exporter): minor enhancements

Fix #2272: allow use of name instead of displayName in exporterHeaderFilter, through new option exporterHeaderFilterUseName
Fix #2232: footer and header need to be in separate sections, not part of content.  Not clear if this is a change at pdfMake end, or never worked
Fix $2336: allow specifying filename for csv, only works in some recent browsers 

Also minor fix to warning from jshint in e2e tests