[squeak-dev] Logging improvements

Hello All,

1. LogTranscript - a minimal log to transcript back end included and
used as default.

2. No longer depends on Kernel-Extensions or Null.

(Only use Null if you want to remove Logging from a minimal image which
still has log calls)

3. LogEngine adaptor now included.

to install:

Installer install: 'Logging'.

regards

Keith