Greasemonkey 1.15 release

The entire list of bugs handled in this release is also available via the 1.15 milestone on GitHub. Note that as always it takes some time for Mozilla to review the new version.  If you're interested in staying on the bleeding edge, try installing the development channel beta release.

If you are using it and notice problems, it's best to log an issue or let us know at greasemonkey-dev (and be clear that it's with this version).

Enhancements:

• Greasemonkey sends headers when making script update checks. (#1824)
• Allow correct installation of even scripts with invalid duplicate UTF-8 BOMs. (#1823)

Fixed bugs:

• Applied a workaround for a Firefox crash that affects scripts which use setInterval() incorrectly. (#1869)
• Fixed enable/disable button state for user scripts in Add-ons Manager. (#1811)