Update/refresh Installing Ceylon IDE page

[jvasileff]

A few items look outdated:

1. "Java 7 requirement" text sounds scarier than necessary. It does acknowledge that it will work with java 8, but then says "Mac OS users must make Java 7 the default". Perhaps simplify the whole section to just say that Eclipse must be running on Java 7 or 8?
2. In the same section, "Java Preferences application located in /Applications/Utilities" no longer exists. This was remove several OS X releases ago
3. When installing the plugin, there are now several more checkboxes - runtime bundles? GEF? (the screenshot is for Ceylon 1.0). Some guidance on which ones to select would be nice.
4. Clicking on http://ceylon-lang.org/eclipse/updatesite/ takes you to a page that claims "information on this page refers to Ceylon 1.1, not to the current release."

[gavinking]

One additional thing I need to do, that is very time-consuming, is update all the damn screenshots.