Update build.sh

line 16 'I' unobtrusive interaction to save re-download of .xz .bz2 sources.
line 322 trailing '/' added
line 323 trailing '/' added
line 323 cd bzimage to vmlinuz because if not $FD = 1 then requires rename to vmlinuz.
line 327 commented out because modules are useful.
line 331 bzimage now vmlinuz
line 333 bzimage now vmlinuz
line 334 bzimage now vmlinuz