Update ui.js

- replaced esDiv with a generic esNode class for greater flexibility
--- added conditionals for cleaner HTML
- added prototypes for events (still need to figure out how to implement correctly)
- modified Node Manager to fit new esNode specifications
--- changed ID numbers to id of element for cleaner searches
- created Post Stack object to handle API queries
- Created "parent" Content Grid object
- Created "children" Search Box and Paginator objects
- Updated makeshift initialization for quick testing using new Node Manager