e6 issue 344 - changes and cleanup for proper handling of the different ...

...debug output choices

1. Modified config.in to really reflect the mutual exclusive options for debug output.
2. Modified debug.{c,h} to not generate superfluous code if no USART is uses and to compile without errors for controllers without USART.
3. Modified usart-config.sh to properly detect zero USARTs if a controller has none.
4. General cleanup of #include-directives.
5. Regenerated all profiles.

Manually tested debug w/usart, syslog and softuart. Compile autotest completes sucessfully w/ minor glitches (cpp-warnings) due to misconfigured profiles (beteigeuze).

This patch introduces a few new config symbols. Please regenerate your profiles by invoking menuconfig "General setup" once.

Review and comment please.