add more json api

Added following json API:

- GET /json/complex/:service_name/:section_name/:graph_name
- GET /json/graph/:service_name/:section_name/:graph_name
    - This is a kind of alias to GET /api/:service_name/:section_name/:graph_name
- POST /json/delete/complex/:service_name/:section_name/:graph_name
- POST /json/delete/graph/:service_name/:section_name/:graph_name
    - This is a kind of alias to  POST /delete/:service_name/:section_name/:graph_name
- POST /json/delete/complex/:complex_id
    - This is a kind of alias to POST /delete_complex/:complex_id
- POST /json/delete/graph/:id

Mainly, what I wanted to add here are below two API functions: 

- GET /json/complex/:service_name/:section_name/:graph_name
- POST /json/delete/complex/:service_name/:section_name/:graph_name
- POST /json/delete/graph/:id

I also added alias APIs just to provide naming consistency for JSON APIs (by following same naming convention with GET /json/graph/:id, GET /json/complex/:id APIs).