And updated doxygen todo list

But not by alphabetical order :P

Adds the option -P --permissive.

Starts implementation for logfiles.

Now -P flag make ttail handle invalid files. When invalid file given the
minmax function set the file pointer and the minmax array to NULL.

May introduce bugs if the binary search function does not handles "holes"
in fp array or in minmax array...

Not done for stdin

Making this function usable by logfiles and stdin format autodetection

Date formats

        Two date formats are allowed for dates arguments (-d , -m) :
        - the same than in the logfile
        - relative from now prefixing the argument with '#-' and given a unit
                - y : year
                - M : Month
                - d : day
                - h : hour
                - m : min
                - s : sec

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

ttail_set_flag_re_ex() and ttail_set_flag_re_ci()

For extended & case insensitive regex

Now we can specify a constant length to cut