make t/30shell.t tests less sensitive to output line order
Report no reanimation even when build_dir empty

This fixes failing t/30shell.t with Expect introduced in
commit 27252dd.
factor prepare() out of make() in CPAN::Distribution (first cut)
factor prereq_for_slot out of unsat_prereq
make MM versus MB choice during prepare, not get
make prepare skip already-written correctly
xdg XXX notes
factor out get() shortcut logic
clean up shortcut_get code

This cleanup preserves the logic, but simplifies the code through
a a more consistent parallel structure

I added additional comments where error handling seemed unclear
or potentially incorrect
have get() return true on success
factor out prepare() shortcut logic
allow customizing t/30shell.t timeout with CPAN_EXPECT_TIMEOUT
Shortcut prereq_pm if no Makefile/Build exists

If configuration aborts with "exit 0", no Makefile and
no Build file will exist.  In such a case, we shouldn't
continue checking for prerequisites.

This avoids a late, confusing warning warning about being unable to read
META if a distribution has no META.  The warning was being triggered at
the end of queue processing, when color_cmd_tmps is called to reset
everything and calls prereq_pm.
rearranging get/prepare shortcut logic
move get's goto check into shortcut_get method
refactor disabled checks
xdg question on isa_perl handling
cleanup prepare() shortcut logic

Also moves when/how some related checks happen in make().
refactor make shortcut logic
refactor test shortcut logic