add sighub signalhandler

* On keyboardinterrupt, the teardown method will executed and the
    statistic will be printed
add returnvalue and output string to the main

return:
0 - on success
1 - if at least one test is broken or were skipped
do not write to error log if all tests finished successful
add filter option

use:
--filter <regex>

to filter your tests, helpful if you wanna execute only one test
do not start testing if no tests available