Fix selector for applying drag-over style
Add alpha state for WYSIWYG editing

Some improvements still needed:
 * Formatting toolbar buttons need icons
 * Buttons may need to have an active state when selecting that formatted text
 * Improve round-trip between textarea and contenteditble
 * Localized strings for prompts
 * Prepopulating link and image URL in prompt when updating value

Tested so far in Chrome and Firefox. Needs testing in Safari and MSIE.

For Automattic/liveblog#97
Supply TinyMCE toolbar buttons for rich text editor
Add HiDPI icons
Eliminate insertImage command since images can be drag-and-dropped
Add support for more keyboard shortcuts for format commands
Ensure editor is initially always inside of a paragraph

 * Use WP switchEditor for wpautop
 * Improve styling of toolbar for Firefox
 * Resize rich textarea based on size of contents
Localize insert link prompt
Reset rich text area and resize upon submission
Add placeholder for rich text area
Improve detection/handling for browsers not supporting rich text
Restore location of edit HTML checkbox
Focus on rich text area when editing a liveblog
Re-focus on the rich text area when dropping image
Fix some jshint errors

js/liveblog-publisher.js: line 61, col 17, Bad line breaking before '&&'.
js/liveblog-publisher.js: line 64, col 17, Bad line breaking before '&&'.
js/liveblog-publisher.js: line 66, col 17, Bad line breaking before '&&'.
js/liveblog-publisher.js: line 149, col 17, Too many var statements.
js/liveblog-publisher.js: line 150, col 17, Too many var statements.
js/liveblog-publisher.js: line 151, col 17, Too many var statements.
js/liveblog-publisher.js: line 174, col 17, Too many var statements.
js/liveblog-publisher.js: line 233, col 17, Too many var statements.
js/liveblog-publisher.js: line 133, col 24, 'switchEditors' is not defined.
js/liveblog-publisher.js: line 211, col 20, 'switchEditors' is not defined.
js/liveblog-publisher.js: line 244, col 25, 'prompt' is not defined.
js/liveblog-publisher.js: line 86, col 39, 'e' is defined but never used.
js/liveblog-publisher.js: line 126, col 49, 'e' is defined but never used.
js/liveblog-publisher.js: line 209, col 56, 'e' is defined but never used.
Merge pull request #102 from x-team/issue-97

Issue 97: WYSIWYG