create directory for source files
The downloads now go into a source folder
Changed to make bzImage, and make mrproper.
Source downloaded to new source folder
Fixed paths
Added comments
Fixed spelling mistake
Merge pull request #2 from BeresfordHare/master

The suggested changes look great and I'm merging them in the current sources. This hasn't tested them yet (TODO) but the changes are quite simple and I believe there will be no issues at all.