Modernize dylan-mode and DIME for Emacs 24

Starting the process of modernizing dylan-mode and DIME assuming Emacs
24 with the intent of packaging it up for distribution on MELPA. Changes
here include:

* Requirement of Emacs 24 to run

* Deletion of all trailing whitespace

* Prefixing of cl- to all CL functions to fix bytecode compiler warnings

* Using defvar-local instead of make-variable-buffer-local + defvar

* defvars of a few symbols that were used without a definition

* Remove of dime-call-defun, which called missing functions and caused
bytecode compile warnings. I'm assuming this didn't actually work.

* Remove of dime-repl-inside-string-or-comment-p, which called missing
functions and caused bytecode compile warnings. I'm assuming this didn't
actually work.

* Removal of portability versions of functions since we can use the real
ones if Emacs 24 is assumed

* Folding of various conds on xemacs, lemacs and GNU Emacs<23 since only
GNU Emacs 24 is supported.

* Allow numbers in module names for header syntax

* Made dylan intentation inherit from standard-indent; added an
indentation variable specifically for continuation lines, defaulting to
2 * standard-indent

* Added syntax highlighting of variable names before :: and of types
after ::

* Remove on-load byte compilation; will ultimately be done by the
packaging manager instead

Signed-off-by: Erik Charlebois <erikcharlebois@gmail.com>