1. Add YOUDAO API.
2. Improve code structure.
Add third explain of webdict of YOUDAO.
Jump to ver 0.2.0

Since many breaks and function name changes, it's neccessary to jump to v0.2.x.
Configuration XML file will be implemented at first. Then goes by Config UI.
Other APIs such as baidu and iciba will be done in next major version.
Igore .plasmateprojectrc
config.ui and main.xml

1. Configuration UI finished.
2. Configuration XML file implemented.
3. UI polishing.
code improvement

replace double quotes with single quotes.
v0.2.0