Code Refactor

Signed-off-by: Pengcheng Bian <pbian@actuate.com>
Code Enhancement: Theme related support.

Signed-off-by: Pengcheng Bian <pbian@actuate.com>
Chart Enhancement.

Signed-off-by: Pengcheng Bian <pbian@actuate.com>
Code Refactor: Themes.

Signed-off-by: Pengcheng Bian <pbian@actuate.com>
Merge pull request #61 from TerryPCBian/master

Code Refactor and enhancement