Rudamentary tail implementation.

For specific info on missing features and optimizations,
look at tail/README.md
Add the ability to install coreutils (resolves #216)
Add some installation instructions
Clarify uninstallation instructions
Merge pull request #228 from Arcterus/install-target

Add the ability to install coreutils (resolves #216)
Merge pull request #225 from molysgaard/master

Rudamentary tail implementation.
md5sum: update rust-crypto
tail: fix build by changing uint to u64
Merge pull request #230 from Arcterus/rust-crypto

Fix build