Bugfix: Fix problems exposed by unit testing.

Bugfix: Fix problems exposed by unit testing.

The default f_color_format_t_initialize should still be provided.

Remove redundant context->set.warning assignments.

Change the logic to not require format strings to be defined thereby avoiding potential segfaults.

Avoid using strnlen() and instead use memcpy().
More memory is used when specifying the sizes, but strnlen() calls probably does this to some extent.
Doing this reduces the number of calls to copying ranges of strings.

Update comments to reflect latest practices.