set_relative_date was failing if the resulting date was in the previous
day.

Add some usefull functions & macro in ttail_check.h for std tests.

And updated doxygen todo list

And bugfixes in _ttail_set_date_relative() bad format detection

In order to not install them.

Now ttail is able to sort logfiles given as arguement.
The sort function _ttail_file_sort place files with no valid date to the
end of the file list and is able to detect if some files overlaps.

No tests written...

Not done for stdin

Making this function usable by logfiles and stdin format autodetection

Four macros were added :
 - TTAIL_CHECK_START(char *test_suite_str, char *test_case_str)
 - TTAIL_SET_FIXTURE(void (*setup)(), void (*teardown)())
 - TTAIL_ADD_TEST( libcheck_test test)
 - TTAIL_CHECK_END

tests/Makfile.am is now generated using tests/regen.sh .
bootstrap.sh has been updated.
Argument parsing tests are splitted

To handle case where none of the file given as argument is readable

Testing ttail_search_closest_files() on multiple files

Set some function inlune and implement an utility function
for file searching functions.

Now we can specify a constant length to cut

The getline wrapper will allow to use getline without calling malloc
and free all the time