Fix regex to handle multiple italic parts in BibLaTeX.js

This solves zotero#1033.

BibLaTeX.js

@@ -323,7 +323,7 @@ function mapHTMLmarkup(characters) {
 	// converts the HTML markup allowed in Zotero for rich text to TeX
 	// since  < and > have already been escaped, we need this rather hideous code - I couldn't see a way around it though.
 	// italics and bold
-	characters = characters.replace(/\{\\textless\}i\{\\textgreater\}(((?!\{\\textless\}\/i{\\textgreater\}).)+)\{\\textless\}\/i{\\textgreater\}/, "\\textit{$1}").replace(/\{\\textless\}b\{\\textgreater\}(((?!\{\\textless\}\/b{\\textgreater\}).)+)\{\\textless\}\/b{\\textgreater\}/g, "\\textbf{$1}");
+	characters = characters.replace(/\{\\textless\}i\{\\textgreater\}(((?!\{\\textless\}\/i{\\textgreater\}).)+)\{\\textless\}\/i{\\textgreater\}/g, "\\textit{$1}").replace(/\{\\textless\}b\{\\textgreater\}(((?!\{\\textless\}\/b{\\textgreater\}).)+)\{\\textless\}\/b{\\textgreater\}/g, "\\textbf{$1}");
 	// sub and superscript
 	characters = characters.replace(/\{\\textless\}sup\{\\textgreater\}(((?!\{\\textless\}\/sup\{\\textgreater\}).)+)\{\\textless\}\/sup{\\textgreater\}/g, "$^{\\textrm{$1}}$").replace(/\{\\textless\}sub\{\\textgreater\}(((?!\{\\textless\}\/sub\{\\textgreater\}).)+)\{\\textless\}\/sub\{\\textgreater\}/g, "$_{\\textrm{$1}}$");
 	// two variants of small caps