Clean up the merging code a bit.

Use the hashtable instead of reusing razor_importer for this.
Introduce struct razor_merger for this. All this is steps
towards making the merging policy external to the core razor_set code.

 CFLAGS = -Wall -g -O2

 LDLIBS = -lexpat -lz -g -lrpm -lcurl

 razor : razor.o import.o sha1.o main.o rpm.o

 clean :

 	rm -f *.o razor