adding signal handler functional tests to dump traceback. should help debug when they freeze
adding signal handler functional tests to dump traceback. should help debug when they freeze

kelcecil/securedrop,harlo/securedrop,kelcecil/securedrop,ehartsuyker/securedrop,ageis/securedrop,jrosco/securedrop,jaseg/securedrop,ageis/securedrop,ehartsuyker/securedrop,garrettr/securedrop,chadmiller/securedrop,pwplus/securedrop,conorsch/securedrop,conorsch/securedrop,jrosco/securedrop,ageis/securedrop,jaseg/securedrop,kelcecil/securedrop,jrosco/securedrop,jaseg/securedrop,GabeIsman/securedrop,chadmiller/securedrop,conorsch/securedrop,jeann2013/securedrop,heartsucker/securedrop,chadmiller/securedrop,pwplus/securedrop,harlo/securedrop,garrettr/securedrop,chadmiller/securedrop,GabeIsman/securedrop,kelcecil/securedrop,heartsucker/securedrop,conorsch/securedrop,micahflee/securedrop,jaseg/securedrop,jeann2013/securedrop,micahflee/securedrop,jaseg/securedrop,pwplus/securedrop,chadmiller/securedrop,harlo/securedrop,ehartsuyker/securedrop,jeann2013/securedrop,ehartsuyker/securedrop,ehartsuyker/securedrop,heartsucker/securedrop,pwplus/securedrop,GabeIsman/securedrop,heartsucker/securedrop,pwplus/securedrop,jrosco/securedrop,conorsch/securedrop,garrettr/securedrop,harlo/securedrop,pwplus/securedrop,jeann2013/securedrop,garrettr/securedrop,harlo/securedrop,jeann2013/securedrop,kelcecil/securedrop,jrosco/securedrop,jeann2013/securedrop,GabeIsman/securedrop,kelcecil/securedrop,jaseg/securedrop,harlo/securedrop,chadmiller/securedrop,GabeIsman/securedrop,micahflee/securedrop,micahflee/securedrop,heartsucker/securedrop,ehartsuyker/securedrop,ageis/securedrop,jrosco/securedrop,GabeIsman/securedrop