"Edit lines" link works, patch implementation missing
Fix: create new story
Application layout converted erb->slim
Add debug info in application layout

This is also a duplicate commit as the previous one is exactly the
same as this...
Add "edit line" but index fix pending

If story contains plot_item that has no character associated then
it will throw an exception. (character_id: nil)
Fix line#index
Put lines#index's edit link to the front
New methods in Line model

seq, plot?, plot (LinesHelper module deleted)
Fix lines#edit view
New lines can be added but:

The whole thing seems to work on the surface but on DB level it is a mess.
A couple examples:
  * STORY[:id].add_character -> merrily saves duplicates
  * CHARACTER also saves duplicates with "create"
    ("find_or_create" is ok)
  * LINE needs to be modified (?) or use special story character ('')
    to distinguish plot and dialogue items

SOLUTION?
  * validations?
  * nothing else comes into mind...
Fix Line.seq in case of no lines in DB