Add main.cpp back and invoke "run" from it

Signed-off-by: Thiago Padilha <thiago@padilha.cc>

run.cpp

@@ -154,7 +154,7 @@ void sigint_handler(int signo) {
 }
 #endif
 
-int main(int argc, char ** argv) {
+int run(int argc, char ** argv) {
     // has to be called once at the start of the program to init ggml stuff
     ggml_time_init();