Null checks for easier troubleshooting

We are getting some errors in the .NET classes for Bitmap and with these
null checks it makes it easier to troubleshoot. I also removed unused
(and obsolete) private methods.
Assembly version 2.4.9
Merge pull request #72 from bherila/master

Fixed typo Metadatda -> Metadata
Fixed moving/renaming of directories in image link tracking
Merge branch 'master' of github.com:n2cms/n2cms
Some tweaks to sql error handler
Changed so UpdateEditor isn't called twice
Added IExceptionFilter and DefaultExceptionFilter to filter exceptions.

Unimportant exceptions can be filtered, which suppresses sending a message.
Simple fix for saving drafts multiple times for items with editable name
Fixed issue with token parsing
Should fix error with future publishing + windsor3
Merge pull request #73 from CarlRaymond/exception_filter

Added IExceptionFilter and DefaultExceptionFilter to filter exceptions.
Merge pull request #71 from christianfredh/master

Null checks in ImageResizer for easier troubleshooting
Assembly version 2.4.9.1
FakeIntegrityManager implements changed IIntegrityManager impl
Fix spelling and remove some code redundancies
Correct delete error text
Remove some code redundancies

ReSharper magic...
Merge pull request #75 from christianfredh/master

Fix spelling and error message, and removed some code redundancies
Merge pull request #74 from faester/versionfix

Simple fix for saving drafts multiple times for items with editable name