Builds the uutils multicall binary containing all utils (except stdbuf)
by default. To only build a subset
`cargo --no-default-features --features <utils>`
can be used.
Whats missing is building the standalone binaries and a mechanism to
automatically disable the build of unix only utils on windows.
I cleaned up string references, whitespace, and use of unstable
features. I also added a comment about reverting to connect, making
others aware that the method should be replaced by join after 1.3.