check return values of strdup and malloc
add talloc0 function (malloc and zero fill)
check return values of arithmetic openssl BN_* functions
check return values of BN_bin2bn function
remove useless BN_init calls right after BN_new
fix 2 small memory leaks
close /etc/passwd file handle right after evaluating home directory
fix small memory leak in running_for_first_time (local variable config_directory)
add length modifier to the format for strings in sprintf call
replace sprintf call with snprintf for downloaded part name
replace sprintf call with snprintf for open image command
remove undefined behavior flush (stdin) call
http://stackoverflow.com/questions/2979209/using-fflushstdin
checking sizeof (void) at the runtime
add field limit for sscanf call (fix libc versions older than 2.13-25)
Merge pull request #34 from antma/master

improve code's style modications