remove unnecessary use of appendChild, fix some whitespace and reserved word errors
add save-generated-files to JBrowse/has, use it in Export feature sniffing.  also add `noExportFiles` config var
replace export View dialog filename textbox with a dijit textbox, looks better in that context.  also associate it graphically with the save button
factor export view-dialog code into a separate method, trying to trim this nasty thatch of code a bit
add save filename to the release notes