Remove statusline and tablines in VimRoom

- Set statusline and tabline to be an empty value in all VimRoom windows
- Remove guitablines with guitablabel-=e
- Move call to Airline Toggle before calls to set statusline and set tabline
Remove gui scrollbars
Clear highlighting in SignColumn
Isolate VimRoom window to own tab page
Save SignColumn highlighting
Replace logic to close vimroom sidebars w/wincmd o
Fix save_signcolumn line in SaveState
Refactor logic to reset highlight groups

- Reset highlight groups individually instead of making a call to ColorScheme
- Use call to s:ResetHighlighting instead
Reset buffer-local navigation mappings
Reset global options
Reset local options. Save locals opts in SaveState
Remove old logic to restore settings
Toggle Airline statuslines back on
Merge branch 'toggle_off'
Remove SaveState function.

- Move functionality to SetLocalOptions, SetGlobalOptions, and
  SetVimRoomBackground