Log messages are not redirected to a provided consumer

[karambaso]

If to set logger using LlamaModel.setLogger then logs are printed to the std out instead of the provided consumer.

It seems that logging was redefined in Utils.cpp which includes log.h and uses a template that never calls the consumer.

To reproduce the bug it is enough just to call LlamaModel.setLogger with LogFormat.TEXT and a consumer that prints to the std out with some prefix.

[vaiju1981]

I have renabled the tests for logging in the PR ( #100), once merged we can revisit this.