* models.py: refactor Blog.save
+ doc: album-dev.md
+ blog/models.py: add dummy album2html
+ models.py: implement album2html
* models.py: link Image and Blog through Image.blog
+ views: add imginfo to get/set image info
+ urls: service media files by Django itself in debug mode
+ edit.html: add upload image button
+ edit.html: upload img and show progress bar
+ doc: uploadimg api
+ edit.html: add id info after img uploaded
+ edit.html: load album raw and covert
* edit.html: add table to display multiple elements
+ edit.html: update img info before submit
* models.py: ignore invalid album cover id
+ edit.html: repack album data for submit
- main.css: disable opacity in context
+ edit.html: disable other options in album mode
+ edit.html: add album cover id
* models.py: fix img tag parse error in bs4

NOTE:
	<img src="img1"><img src="img2">
beautiful soup will be covert it into:
	<img src="img1"><img src="img2"></img></img>