include entry functions in design doc

[http://dummy.us.eu.org/robert (Robert)]

bool hits_queryfunc(const char*)
void hits_runfunc(const char*, int* int_in, const char** str_in, double* real_in, int* int_out, size_t num_int_out, char** str_out, size_t num_str_out, double* real_out, size_t num_real_out)