Single blank lines in initial editor content are doubled.

[davelozier]

Single lines <p><br></p> in initial editor content are doubled to <p><br></p><p><br></p>. Also, an extra blank line is added to the end of the initial content.

Steps for Reproduction

1. Visit http://codepen.io/davelozier/pen/KMgNze
2. Within the HTML you can see that there are no double blank lines nor one at the end of the initial content being edited.
3. Observe that the editor itself shows double blank lines in place of the single ones and has an additional blank line being appended to the initial content being edited.

Expected behavior: Single blank lines in initial content should not be doubled. No additional blank line should be appended to the initial content being edited.

Actual behavior: Single blank lines in initial content are doubled. An additional blank line is appended to the initial content being edited.

Platforms: Chrome 51 on Linux (Ubuntu 16.04) - Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.103 Safari/537.36

Version: 1.0.0-beta.5