add Login support
1. add API for login & del/edit post
2. add postController & loginController
3. add bootstrap-confirm.js for showing confirm dialog

todo: del post need to update Terms, edit post is not implemented.
will implement after add post is finished.
1.change notification sytle, show notification in center bottom now
2.add css support for bootstrap-confirm dialog, usage:
  showDialog(
    css: {"width": "90%", "height": "900px", "left": "5%", "margin":
"auto"}
  )
  will make dialog wider and center
3.add Admin panel in siderbar, will be optimised later
4.remove duplicated pagination id
5.move initLogin() call to the end of this script, after calling
ko.applyBindings(data);

6.add post edit area & edit.html, todo...
1. load tinymce script dynamically
2. add terms cache in getCategories()
3. savePost() todo...
1.add format method to Date
2.add create method to Posts, setting default values for new Posts()
object
3.new post saves ok, need to update TermRelations...
  note: use tinyMCE.get('post_editor').getContent() to retrieve editor's
content
1. move term_taxonomy_id column to term_id for TermRelationships table
2. update TermRelationships and update Terms count for posting new article
API_parse: doSavePost, doSaveRelationship, doSaveTerm
refactor PostController, add PostEditorModel
1. add to PostEditorModel: fillCategoryOptions, fillFromPostModel
2. add to PostModel: setTag, getTag, fillFromPostEditorModel
3. fix edit post, now saves ok.
1. delete post ok.
2. check terms count.
add private status in Post title
fix bug: when editing a post, change the category, then click save button,
the newly added relationship may be deleted during deleting old relationships.