Fix pagination limit in Nodes promoted() action

Closes #326
Fix: Avoid blackhole by setting nodes.body

Closes #336
Reported-By: slighlychilled
Fix: Remove extra key for user data

Closes: 322
Related: b0e5ed6016c94d7e3e62381480fe61f1441b68b8
Make button class uniform

Closes #333
Display theme screenshots in thickbox

At the same time, fixes an issue where active theme screenshot
overflows.
FormHelper: Updating old usage of 'rel' to 'help'
Fix: Deprecated use of `$this->params`

Closes #344