Pale Moon 27.0.0

# New and updated features:
- Support for DirectX 11 and Direct2d 1.1 on Windows. This will bring Pale Moon more in line with the capabilities for current-day operating systems and graphics hardware.
- Update of the Goanna engine to 3.0 - with many changes to layout and rendering for the modern web.
- Pale Moon now fully supports HTTP/2.
- Ruby Annotations are now an integral part of the HTML parser, controllable with CSS.
- Media Source Extensions have been implemented to solve many video playback issues.
- This can be enabled/disabled and configured in Options. It's recommended at this time to not enable MSE for WebM since there are a few issues with it on services like YouTube (e.g. losing audio when looping/skipping).
- Support for reading and playing so-called "fragmented" MP4 files has been added, further solving media playback issues.
- Support for SSL/TLS connections to proxy servers.
- Support for the WOFF2 font format for downloadable fonts.
- The JavaScript engine has been updated with support for many landmark ECMAScript6 features (chief among them promises and generators). This will solve many of the web compatibility issues that people have started to run into in the past few months (e.g. webmail interfaces, some sites coming up blank because they are script-generated).
- The way web content is cached has been changed to be more efficient. If you want to immediately take advantage of this, clear your cache.
# Removed support/features:
- Removed support for Windows XP. If you are still running Windows XP, then your only option is to continue using Pale Moon 26.
- Removed the internal PDF (pre)viewer. This module was not maintained, was unable to display even half of the PDF documents correctly, and could not reasonably remain included in the browser. Please use a separate reader and/or install a PDF reader plugin.
- Disabled building of the devtools. They will not be included in release versions of Pale Moon from this point forward. If you are a web developer or otherwise need those tools, fear not! They are available as a browser extension.
- Removed the active XSS filter. This feature, although effective, was prone to some instability and needs to be rewritten for the update of our platform. It may or may not return in the future, depending on whether the original author has time to rewrite parts of this filter implementation.
- Removed support for Add-on SDK extensions (JetPack extensions), considering the Mozilla/Gecko SDK is no longer compatible with our combination of application and platform code.
# Security highlights:
- All relevant security fixes up to and including Firefox 50 have been ported across from Mozilla to continue to provide an as secure as possible browser.
- Several libraries have been updated to their latest versions to pick up any important vulnerability fixes.
- There's a new option and control to determine whether to save zone information (marking files as "downloaded from the Internet") on downloaded files (Windows+NTFS). You can find this in Options.
# Other important notes:
- Pale Moon 27 will initially only be available in English. We are working on getting localization done to have language packs available over time.
- Important: You can not use the previous language packs since many strings have changed. Trying to do so will likely prevent the browser from starting or functioning. Pale Moon will automatically disable language packs for the previous version, but if you have explicitly disabled add-on compatibility checking you may run into trouble.
- We will continue to fully support the following:
* NPAPI plugins
* Extensions with binary/XPCOM components
* XUL/Overlay and bootstrapped extensions
* Complete themes
* Unsigned and author-signed extensions
* The Camellia encryption cipher (also in GCM mode)
* Graphite font shaping
* Sync 1.1 (albeit without support for syncing add-ons)
* Full customization of the UI as before