Improve error handling/logging

[SicorDev]

Hi there,

the syslog of many typo3 installations is full of messages like this one:

A transformation could not completed: An exception was thrown while transforming the value. The message was:

It would be really helpful if the exception would output some information regarding the problem itself, like the URL and in which line in the source the exception was thrown.

If you give me a hint, i could take a closer look.

[thommyhh]

The logging should be improved in general and, of course, should contain more helpful information.

Btw: I've already changed the logging from using the sys_log table to use the TYPO3 logging mechanism, that i, by default, writing a log file in typo3temp/logs/.