Move the passwordderivebytes zip to /files and add bullet point in hi…

…ghlights

I prefer centralizing binaries in the top level folder instead of having them randomly scattered around the repo.

README.md

@@ -54,6 +54,7 @@ Repository structure
  - `css` - contains the main stylesheet
  - `docs` - contains the source pages for the `/docs` website section
  - `download` - contains the source pages for the `/download` website section
+ - `files` - stores binary files used in pages
  - `images` - stores the images used in pages
  - `news` - lists the blog pages from the `_posts` directory
 

docs/about-mono/releases/4.2.1.md

@@ -9,6 +9,7 @@ Highlights
 ----------
 
 * More adoption of Microsoft's open source code
+  * this causes a small PasswordDeriveBytes compatibility breaking change, see below
 * Support for PPDB debugging format
 * New threadpool implementation
 * Runtime optimizations
@@ -213,7 +214,7 @@ If your application requires consistent behavior from `PasswordDeriveBytes` (for
 
 * If you extract no more bytes than the hash length (for SHA-1, the default, this is 20 bytes) from `PasswordDeriveBytes`, the behavior will be identical between all versions of Mono and Microsoft .NET.
 * If you need compatibility with applications targeting Microsoft .NET, use the `PasswordDeriveBytes` in `System.Security.Cryptography`.
-* If you need compatibility with applications targeting Mono 4.0 or previous, you can download [this package](mono-old-passwordextendbytes-4.0.5.1.zip), which contains source for a Mono 4.0-compliant version of `PasswordDeriveBytes`.
+* If you need compatibility with applications targeting Mono 4.0 or previous, you can download [mono-old-passwordderivebytes-4.0.5.1.zip](/files/mono-old-passwordderivebytes-4.0.5.1.zip), which contains source for a Mono 4.0-compliant version of `PasswordDeriveBytes`.
 
 For new development, we recommend avoiding `PasswordDeriveBytes` entirely and using `Rfc2898DeriveBytes`, which is standard-compliant (PBKDF2), more secure, and does not have the compatibility issue.