Improved "semicolon-style" in src/*.lisp

* src/conditions.lisp: use standard "semicolon-style", not Emacs-like
* src/variables.lisp: likewise
* src/ffi.lisp: likewise
* src/connection.lisp: likewise
* src/daemon.lisp (header): updated copyright
  use standard "semicolon-style", not Emacs-like
Added version/{list,string} functions in network.spread.asd

* network.spread.asd (package network.spread-system): added exported
  symbols version/list and version/string
  (+version-major+): new parameter; major version component
  (+version-minor+): new parameter; minor version component
  (+version-revision+): new parameter; revision version component
  (version/list): new function; return version as list
  (version/string): new function; return version as string
  (system network.spread): use `version/string'
  (system network.spread-test): likewise