[sample] Remove XML styles

- These style files are not must for the samples, and
  they are from testkit-lite repo under GPL 2.0 License
[sample] Remove trailing space from suite.json
Merge pull request #817 from zqzhang/remove-xsl

[sample] Remove XML styles
[sample] Rename webapi-sample-tests to DemoExpress and sort case names

 Unit test platform: Android
 Unit test result: all tests run well
Merge pull request #819 from Honry/Honry/rename-sample

[sample] Rename webapi-sample-tests to DemoExpress and sort case names
Replace blue.png with blue-100x100.png
Format .html of DnD sample