Split into multiple files, begin init_loop, adjust read

Makefile

@@ -1,3 +1,5 @@
-all: allocator.o blockstore.o
+all: allocator.o blockstore.o blockstore_open.o blockstore_read.o test
 %.o: %.cpp
 	gcc -c -o $@ $<
+test: test.cpp
+	gcc -o test -luring test.cpp