Setup sensible plugin styling to go with the new header.
Fix model completion code broken by API changes.  Thanks to @regoo for pointing this out.
Remove unused code.
Add an optional parameter to the hello world for purposes of pedagogy.
Reorganize the web-client directory for clarity, consistency.
Cleanup the GET-Model handler in preparation to convert all models to plugins.
Allow marking plugins to specify different HTML markup at the top and bottom of a page.
Add a more complex sample marking plugin.
Allow model markings to be changed.  Closes #272.
Cleanup the interaction between plugin model markup and markings.
Fix a regression displaying markings with legacy models.
Header automatically closes models.  Closes #273.
Display error message popups in the open model menu.
Cleanup plugin model and navbar files.
Display alerts for failed or incomplete models.  Closes #274.
Set a better default style for model content.
Testing flexbox.
Merge https://github.com/sandialabs/slycat into regoo

Conflicts:
	packages/slycat/web/server/handlers.py
	web-server/js/slycat-navbar.js
	web-server/templates/slycat-model.html
为平行坐标添加grid