Deleted old argument struct tm* from search function (now using infos
stored in ttail_t.session )

add a -h --help option, deleted -l --logfile options
+ spliting the ttail_search_closest() & ttail_search_print_res() functions

Now we have a running minimal ttail :
src/ttail -d "Mar 6 00:29" -f '%B%n%d %H:%M' -l tests/samples/1.log -l tests/samples/1.1.log