Faster user search, improved history feature and more bugfixes

Today's update (4920618) brings with it the following changes:

Performance improvements

The user search now uses an indexed search method, making it much faster. This has a side-effect that pure substring search is no longer possible. You can now only search on full tokens (like the full name or email).

The read request handler and embed template function are now history-aware. This feature enables the history request handler to show the historic content of objects that use data request handler to refer to the content, like images, videos and other binary content. The thumbnail, watermark and wav2mp3 request handlers have also been made history-aware.
- The following object types don't support relative file references (because they use resolve_path) when viewed using history:
  - Flash apps
  - JavaScript apps and scripts
  - SVG images
  - Perl scripts
  - CSS stylesheets
  - Text files
  - XML files
- Java apps don't support history viewing at all (because they use resolve_path which doesn't support history).
- Zip files can't be unpacked from history, they must be restored first. You can download them, though.
The embed template function now supports render_mode => "source" on JavaScript and CSS.

It is now possible to restore a deleted object or container into the correct parent container. The parent container must exist, or you'll get a database error during restore. Be aware that the parent container must be restored before the child object or container, or you'll get a database error about missing parent. This is most likely to occur when trying to restore a recursive delete.
Some flash info messages are now considered redundant and are not shown during normal usage.

Small change in behavior. If embed template function is called with an odd number of options the options variable is now empty instead of cut at the last missing key/value pair. This should make the error in API usage more obvious. This could potentially trigger some regressions in content that was previously working.
The user search feature wasn't able to search for firstname lastname after a recent update. This has now been fixed.
A regression was found in the matchbox quiz type, which could return invalid data from the database when used together with the history-aware feature.
The links to Bokmålsordboka and Nynorskordboka have been updated.
Whitespace is now trimmed when using the history request handler.
Backend importing of content was not possible because the cost and copyright boolean object attributes where not sent properly to the database. This has now been fixed.