Now jenv could run in zsh, but not sure about the compatibility with bash.
Add an argument to identify zsh or bash.
Remove echo and add file .gitignore
Fix install bug when candidate version is not provided in zsh.

ZSH's array index is not started with 0 but 1.
ZSH completion support.
Fix install bug in zsh and add zsh install guide to README.md
Merge branch 'master' of git://github.com/khotyn/jenv into khotyn-master

Conflicts:
	.gitignore
Fix selfupdate problem in zsh.
Modify install.sh, install.sh now will let user chooose their shell,
bash or zsh.
Add command reinstall to zsh completion.
Fix jenvrc problem in zsh.
Fix zsh problem according to the lastest code.

TODO:

* Provide candicate version support in zsh completion.