add 09-MoreAboutVariable

They are under constraction

modified 09-index

finished to write 09-index

more modified index-09

more more modified index-09

more more more changed 09-index

add 09-ex
modified 09-index
Update index.md

Reflect @Vault690 's point out.
fixed 09-index
Merge pull request #12 from techfun-org/dev-09-pr

add 09-MoreAboutVariable