pdf-util.js: Simplify MuPDF object.
pdf-util.js: Use explicit type conversions in AFParseDateEx and AFParseTime.
pdf-util.js: Always use strict equality comparisons.
pdf-util.js: Hoist var statements out of for statements.

Make the scoping clearer, since Javascript doesn't have block scoping.
pdf-util.js: Fix some regexps.
pdf-util.js: Improve alert messages (also include the event value).
pdf-js.c: Cluster test fixes.

Use a fixed number for Math.random().
Return a fixed date for Date.now() and Date.UTC().
pdf-js: Pass a name string to type constructor.
Add function for creating form fields (widgets)

This feature is being implemented mostly for the purpose of permitting
the addition to a page of invisible signatures.

Also change pdf_create_annot to make freshly created annotations
printable by default.