Add feature to edit and synchronize blogs from local files

The ability to download, edit, and synchronize blogs from local files would save more time for HubSpot CMS users than any existing feature barring theme editing (which is also a huge time saver). Clicking around a web browser and interacting with WYSIWIG editors is orders of magnitude slower than using Vim, for example, to rapidly open, edit, and save files. With https://github.com/tpope/vim-unimpaired, one could rifle through hundreds of blogs using ]f whereas in the browser, the same task would be impossibly inefficient.