Merge pull request #3 from xfguo/without-oo

Rewrite the actor, the i/f become simple and clean and without OO.
Clean up examples.

Signed-off-by: Xiongfei(Alex) Guo <xfguo@credosemi.com>
Minor typo bug fixed and better doc.

Signed-off-by: Xiongfei(Alex) Guo <xfguo@credosemi.com>
Totally remove OO from **Luactor**.

Signed-off-by: Xiongfei(Alex) Guo <xfguo@credosemi.com>