Implement new functions of NVIM API v4

[esensar]

Implement new functions added in NVIM API v4. These functions can be discovered using API Explorer from this project. All of this belongs to neovim-api module and wrappers need to be made in neovim-rx-api module for RxJava support.

These are:

• Functions:
  • nvim_get_proc - https://neovim.io/doc/user/api.html#nvim_get_proc()
  • nvim_get_proc_children - https://neovim.io/doc/user/api.html#nvim_get_proc_children()
  • nvim_list_uis - https://neovim.io/doc/user/api.html#nvim_list_uis()
  • nvim_parse_expression - https://neovim.io/doc/user/api.html#nvim_parse_expression()
  • nvim_list_chans - https://neovim.io/doc/user/api.html#nvim_list_chans()
  • nvim_get_chan_info - https://neovim.io/doc/user/api.html#nvim_get_chan_info()
  • nvim_set_client_info - https://neovim.io/doc/user/api.html#nvim_set_client_info()
  • nvim_get_commands - https://neovim.io/doc/user/api.html#nvim_get_commands()
  • nvim_call_dict_function - https://neovim.io/doc/user/api.html#nvim_call_dict_function()
• Methods:
  • nvim_buf_get_commands - https://neovim.io/doc/user/api.html#nvim_buf_get_commands()
  • nvim_buf_detach - https://neovim.io/doc/user/api.html#nvim_buf_detach()
  • nvim_buf_attach - https://neovim.io/doc/user/api.html#nvim_buf_attach()

[esensar]

This is already implemented.