Merge pull request #193 from ebfe/fix-build-master

Fix build with rust master
add uutils multicall binary
head: unwrap IoResult before printing
Merge pull request #196 from ebfe/fix-head

head: unwrap IoResult before printing
modified:   .gitignore
Update .gitignore
Merge pull request #197 from Heather/master

modified:   .gitignore
silence dead code warnings in multicall build
multicall: don't build true/false crates
Merge pull request #195 from ebfe/multicall

Add a multicall binary
Improve cat performance
Merge pull request #189 from mahkoh/cat

Improve cat performance
remove todo
Merge pull request #199 from mahkoh/readme

remove todo
remove remaining uses of ~[T]
Merge pull request #202 from ebfe/remove-tilde

remove remaining uses of ~[T]
Update to nightly
Add a 'busytest' target to run uutils under the busybox testsuite

It requires the BUSYBOX_SRC environment variable to be set,
and optionally passes arguments to the busybox test runner with
the RUNTEST_ARGS environment variable.

Example:

```
make busytest MULTICALL=1 BUSYBOX_SRC=~/dev/busybox RUNTEST_ARGS=tr
```
Output list of uutils functions in a way that busybox's 'runtest' understands
Improve busybox compatibility for command line processing