add original
translate introspection
Fixed original doc link
Merge pull request #16 from mitsuruog/master

Introspection
Fix review for variables

監訳終了。
Fix review for interpolation

監訳終了。
Fix review for operators

監訳終了。
Merge pull request #17 from mitsuruog/master

[監訳済] Variables Interpolation Operators
Fix review for keyframes

監訳終了。
Fix review for extend
Fix review for functions.url

監訳終了
Merge pull request #18 from mitsuruog/master

[監訳済] Keyframes Extend url()
translate Comments
Merge pull request #19 from japboy/Comments

[監訳希望] Comments
add original doc
ja translation