Copy .bash versions of setchplenv to .zsh version.
bash -> zsh
Cleanup output of .sh versions of setchplenv.

Use printf to print strings that should not have a new line char. I copied the
.bash versions and substitued `printf` for `echo -n`.
Add %s format argument to printfs
Revert "Add %s format argument to printfs"

This reverts commit 0b7d971c49504e3b5ba024c6faa1079ecb4d26c4.
Revert "Cleanup output of .sh versions of setchplenv."

This reverts commit ba26a7031d1886155ebcdd8fd8e3a4de09bece37.
Revert "bash -> zsh"

This reverts commit 8abe3ce896c07d583927315bd8c9f1e7220e4103.
Revert "Copy .bash versions of setchplenv to .zsh version."

This reverts commit a0f8481be45796171b91f7b9425edefaf97a366a.
Add zsh to the list of shells that are bash-compatible.
Merge branch 'master' of github.com:chapel-lang/chapel into zsh-setchplenv
Merge pull request #611 from thomasvandoren/zsh-setchplenv

Update README to mention zsh as a bash-compatible shell.