Lots of refactor, editing sweet and few more functionality

  - Refactor views to abstract a lot of logic to models
  - API for editing sweet
  - Permalink(non-API) to see a specific sweet
  - Frontend async code to edit sweets. (It would be better, IMO, if we can
    make the frontend of swtstore a separate app).
  - Change few APIs to be better. (Like previously to list a user's apps or
    contexts; one would go to /apps or /contexts; now it is /users/me/apps and
/users/me/contexts, also added /users/me/sweets).
  - Move a lot of debug print statements to a logger component.