Closes #5: don't ask irrelevant questions on sly-quit

Also don't on `sly-disconnect'

* sly.el (sly-auto-select-connection): Use `sly-prompt-for-connection'
(sly-connection-close-hook): Tweak message.
(sly-prompt-for-connection, sly-auto-select-connection)
(sly-select-connection, sly-cycle-connections-hook)
(sly-cycle-connections): Move below, keep unchanged.
(sly-prompt-for-connection): New function.
(sly-quit-lisp): Use `sly-prompt-for-connection'
(sly-eval-macroexpand-inplace): Fix byte-compiler warning.
Update NEWS.md
Closes #13: Make "C-c C-z" bring up any good REPL

* sly-mrepl.el (sly-mrepl): Bind "C-c C-z" to `sly-mrepl'
in SLY's editing mode map. Thanks to Javier Olaechea for idea.
Closes #14: XREF results now legible on Emacsen < 24.4

* sly.el (sly-xref-button): Return actual label for Emacs < 24.4
Fix history inspection in sly-mrepl

* contrib/sly-mrepl.el (sly-mrepl-part): New "describe" and "inspect" actions.
(listener): Set result-counter to -1.

* contrib/swank-mrepl.lisp (with-eval-for-repl): New macro.
(eval-for-mrepl): Use it.
(inspect-entry): Use it.
(describe-entry, pprint-entry): New functions.
Allow sly-disconnect and sly-quit-lisp to be called non-interactively

* sly.el (sly-disconnect): Add `interactive' arg.
(sly-quit-lisp): Add `interactive' arg.
* README.md (Fork): Explain the "why of SLY"
Fix gray stream issue for SBCL

The pretty printer seems to call the non-standard
stream-line-length generic function.

* lib/lisp/backend/swank-sbcl.lisp (sb-gray:stream-line-length):
  Implement default.

(cherry picked from SLIME commit
b3bd68064b2012eca6b61cc938288f6c245acbe9)

Conflicts:
	ChangeLog
Minor cleanup in slime-parse-tests.el

* test/slime-parse-tests.el (form-up-to-point.1): Don't
hardcode swank::%cursor-marker% use the slime-cursor-marker
constant instead.

(cherry picked from SLIME commit
228285b8bee3289c28e6a8b086174d7ce1be5cfd)

Conflicts:
	contrib/ChangeLog
	contrib/test/sly-parse-tests.el
Only test contribs that actually have tests.

* Makefile (CONTRIB_TESTS): New variable.

(cherry picked from SLIME commit
fac577dd49c2e3d716d7ebef801d5ef4f7ce668b)

Conflicts:
	contrib/ChangeLog
	contrib/Makefile