Write blog posts for humans

* Polish blog-post language for a less-technical crowd
* Emphasize that it's not a core issue
* Emphasize that it doesn't affect sites without plugins
* Break into paragraphs for easier skimability
* Explain that it affects users with access to templates, not just plugin authors
:lipstick:
get the version # right
s/you are may/you may/
Merge pull request #1353 from benbalter/1-1-2-blog-post

1.1.2/1.0.4 announcement posts improvements
Update history to reflect merge of #1353