finetune : print sample-start/include-sample-start (#5072)

This commit adds `--sample-start` and `--include-sample-start` to the
output from the main function in finetune.cpp.

The motivation for this is that even though these are set explicitly by
the user via the command line, if one forgets to set them then it is
useful to have their values printed out. Otherwise it is possible to go
through the whole training process before realizing that the values are
not what one expected.

Signed-off-by: Daniel Bevenius <daniel.bevenius@gmail.com>