non-blocking getch()
put LDFLAGS at the end
add thread status variable
clean synchronized() and the different calls
init mutex after
check arguments number using argc and optind
improve usage display
implement push function

Pushing 'p' now opens the file in your
editor and when quitting it later,
the search results are still present.

Pushing Enter has the old behaviour.
add README installation
fix blocking thread while a file is open

Fixes #20
remove double '/' on file name only
use push with Enter as well
add autotools
add missing libconfig-dev header dependency