update ex3
Merge branch 'master' of https://github.com/mattmilten/appfs
Merge pull request #16 from bzfhoppm/master

added ex2
Update README.md
Merge branch 'master' of https://github.com/mattmilten/appfs
Update README.md
Update README.md
Merge branch 'master' of https://github.com/mattmilten/appfs
add new exercise ex4
Update README.md
Update README.md
add some helper files for ex4
update README
Update README.md
Update README.md
Update README.md
source code for ex4 added in dir ex4/hoppmann

Note: allocate.c and allocate.h in dir ex4 is also used for this program