[#16] "Article" represents a page or a post which consists of web-sites.
[#16] "List" represents a post-list which consists of web-sites.
[#16] "UrlJoin" generate a relative location from fragments of a URL.
[#16] An instance of "List" should have a method "Content".
[#16] An instance of "List" needs not have a list of "Article" instances.
[#16] "UrlJoin" requires variable-length arguments. Each of them is typed as string.
[#16] Convert values typed as int to string to generate the location from them.
[#16] Rename "_list.go" to "content_list.go" to build.
[#16] Fix: Rename "Article.time" to "Article.date" to avoid name collision.
[#16] "Article" should not have a getter method "Content".
[#16] "List" should not have a getter method "Content".
[#16] Fix: The "reciever" of "parseFileName" should be "Article".
[#16] Rename recievers to avoid using "this" variable.
[#16] "Builder.Build" is responsible for generating contents and writing them.
[#16] Move the main command into "cmd/inkt/".
[#16] Generate article-lists if "needList", which is an argument of "Builder.buildContents", equals true.
[#16] Do away with "Directory.Iterator" to avoid redundancy.
[#16] Ignore directories when contents files are iterated.
[#16] Inkt will build contents incrementally.
[#16] Change the order of field initialization to avoid not calling "Builder.Dispose".