documentation for commands in 'extending bakefile' section (based on patch #1470414 by Francesco Montorsi)
documentation for commands in 'extending bakefile' section (based on patch #1470414 by Francesco Montorsi)

git-svn-id: bd2c15cabedda08daa94fbf2043b3f8588072843@918 34294538-1d18-489e-82e9-bb8ff975a0eb

Distrotech/bakefile,Distrotech/bakefile,Distrotech/bakefile,Distrotech/bakefile