Bulletproof the test suite and examples; version bump the cabal file.

The examples in the man page used the "<<<" syntax which is specific
to bash. Now "echo 'foo' | hath ..." is used, and that should work in
any shell. The shelltest suite was updated to use the same.

The two ShellTests(Net) modules were also updated to run the
shelltests with an empty environment. This allowed the --color=never
argument to be removed from the tests themselves, since $GREP_OPTIONS
can't be populated.