Added more tests + fixed evstr issues

tests/ev_str/find_all_count_only.c

@@ -0,0 +1,15 @@
+#define EV_STR_IMPLEMENTATION
+#include "ev_str.h"
+
+#include <assert.h>
+
+int main(void)
+{
+  evstring text = evstr("Hello, this is me saying `Hello` like someone who says 'Hello'");
+
+  assert(evstring_findAll(text, evstr("Hello"), NULL) == 3);
+  assert(evstring_findAll(evstr("abc"), evstr("abc"), NULL) == 1);
+  assert(evstring_findAll(evstr("abcx"), evstr("abc"), NULL) == 1);
+
+  return 0;
+}