Added md5sum column for Message IDs in Article table.

MessageIDs can be very long strings, at least in theory. This is why
the corresponding field in the article table is defined as to be
quite long.

The problem is, an index on a large field is not usable in MySQL.
We got feedback from a MySQL optimization consultant we should
remove this.

Also, on SQL Server databases, the index on the message_id column
can potentially cause trouble, because the column is too big.
This would mean some (larger) message IDs can not be inserted.

This patch fixes the issue by introducing a column that stores
the md5sum of the message id, and by introducing an index on
this much smaller column.

Apart from that, when implementing this, I found the
message_id was also present in the article_search_index table
but was not used at all, so I dropped this column and
corresponding index from the table.
Added perl replacement script for otrs.cleanup.

The original otrs.cleanup script is a BASH script and thus can not run
on Windows environments.

Fixes bug#[9381](http://bugs.otrs.org/show_bug.cgi?id=9381)
Added widgets to the Admin Notification Event view.
Fixed HTML structure.
Removed explicit value in auto-increment field.

Otherwise we could run into trouble on systems with large number of
lines in the history type table. Thanks MG for the suggestion!
Fixed duplicate "my" declaration.
Removed reference to no longer bundled File::Temp
Fixed bug#9421: article ignored in article search index if body is almost empty.
The StaticDB fulltext search backend is now fully configurable.
Fixed bug#9458 - Double click on Transition opens error message.
Fixed bug#9459 - Creating a new transition action coming from the transition path view produces errors.
Moved X-UA-Compatible info from html meta tag to HTTP header for better html validation.
Added more X-UA-Compatible http headers.