Add function to retrieve emacs-ycmd version
Add function to retrieve emacs-ycmd version

Add function `ycmd-version` for getting emacs-ycmd version as string. Add also
more information about the current system to ycmd-show-debug-info output which
could help to track down reported issues.

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