Updated README.
Updated README.

* Fixed heading level
* Added note about spacemacs wackiness

emacsmirror/ycmd,emacsmirror/ycmd,ptrv/emacs-ycmd,ptrv/emacs-ycmd,phst/emacs-ycmd,emacsmirror/ycmd,emacsmirror/ycmd,phst/emacs-ycmd,abingham/emacs-ycmd,abingham/emacs-ycmd,emacsmirror/ycmd,emacsmirror/ycmd,ptrv/emacs-ycmd,abingham/emacs-ycmd,ptrv/emacs-ycmd,ptrv/emacs-ycmd,abingham/emacs-ycmd,phst/emacs-ycmd,phst/emacs-ycmd,abingham/emacs-ycmd,ptrv/emacs-ycmd,abingham/emacs-ycmd,phst/emacs-ycmd,phst/emacs-ycmd