WIP: External tests

Some API changes and (upcoming) patches to automate the testing of Pd-l2ork externals.

"External tests" might be a bit of a misnomer as the tools should be usable for testing internal classes as well.

Ideally, the tests would do the following:

1. load all libs in the relevant libdir
2. fetch the list of new creator names that came from loading the libraries in the libdir
3. try to create an object using each new creator name (with required args if necessary-- unfortunately some externals fail)
4. for each successfully instantiated object, enumerate the methods and call each one with whatever args are required.
5. check the output against the output we saved from the previous release (of course this implies saving changed state in each release as necessary)
6. for each dsp method, output a single block of audio using [switch~] (probably want to check against known good state, too, but that may create a lot of state)
7. report any new method and new creators

The nice thing is that we can use a nonzero arg to "menuquit" in order to signal to CI that there was a failure in any of these steps.

This will allow us to more easily make changes to the codebase. Not only external libraries but also the build system and core, as any soft failures (of which there are many in the build system) that screw up something in an external lib will (eventually) trigger a hard failure in this test framework.

Difficulties

1. State-saving and other side-effect-based methods. For now we might have to exclude certain methods like "write" or "read" that are more difficult to test using such an automated framework.
2. "helper" creators and methods. Some objects have "proxy" objects with their own class names. However, I think such objects have their constructors disabled. It may be possible to add a check for that in [classinfo] and thus skip these. (Not sure what to do about "helper" methods, though.
3. Probably lots of other problems I'm not thinking of yet...

scripts/external-tests.pd

-#N canvas 154 25 751 635 12;
+#N canvas 162 25 751 671 12;
 #X msg 513 70 bang;
 #N canvas 273 114 533 496 get_extensions 0;
 #X obj 17 44 inlet;
@@ -501,10 +501,7 @@ may be other oddities in external libs with regard to libdir prefixes.
 #X obj 102 163 f;
 #X obj 102 188 + 1;
 #X msg 274 263 set;
-#X msg 66 307 \$1 \, \$2 \, \$3 \, \$4 \, \$5 \, \$6 \, \$7 \, \$8
-\, \$9 \, \$10 \, \$11 \, \$12 \, \$13 \, \$14 \, \$15 \, \$16 \, \$17
-\, \$18 \, \$19 \, \$20 \, \$21 \, \$22 \, \$23 \, \$24 \, \$25 \,
-\$26 \, \$27 \, \$28 \, \$29 \, \$30 \, \$31 \, \$32 \, \$33 \,;
+#X msg 66 307 \$1 \,;
 #X obj 66 263 list;
 #X msg 102 263 adddollar \$1 \, addcomma;
 #X msg 150 126 0;
@@ -719,22 +716,25 @@ maxlib memento mjlib motex osx pddp pdogg pixeltango pmpd rradical
 sigpack smlib unauthorized vbap pan freeverb~ hcs jmmmp ext13 ggee
 iem_anything ekext hexloader disis lyonpotpourri;
 #X obj 37 44 t b b b b;
-#N canvas 340 199 450 300 libs_not_loaded_by_default 1;
+#N canvas 319 177 550 418 libs_not_loaded_by_default 0;
 #X obj 10 11 inlet;
-#X obj 10 231 outlet;
+#X obj 10 251 outlet;
+#X text 104 243 problems;
+#X text 104 263 iem_tab: 45 classes that refuse to create without args
+;
+#X text 104 283 tof: param class is too complex to easily give default
+args;
 #X msg 10 36 adaptive arraysize autotune~ bassemu~ bob~ boids bonk~
 bsaylor choice comport controctopus fluid~ hid iem16 iem_adaptfilt
 iem_ambi iem_bin_ambi iem_delay iemgui iemmatrix iem_roomsim iem_spec2
-iem_tab iemxmlrpc jasch_lib K12 la-kitchen loop~ lrshift~ memento-p
-mjlib moocow moonlib motex mrpeach nsend pan pd~ pdcontainer pd-wavelet
-pique plugin~ pmpd purepd rjlib rradical rtc sfruit sigmund~ stdout
-timestretch tof windowing;
-#X text 110 172 ratchet up as we go;
-#X obj 10 173 list split 12;
-#X connect 0 0 2 0;
-#X connect 2 0 4 0;
-#X connect 4 0 1 0;
+iemxmlrpc jasch_lib K12 la-kitchen loop~ lrshift~ memento-p mjlib moocow
+moonlib motex mrpeach nsend pan pd~ pdcontainer pd-wavelet pique plugin~
+pmpd purepd rjlib rradical rtc sfruit sigmund~ stdout timestretch windowing
+;
+#X connect 0 0 5 0;
+#X connect 5 0 1 0;
 #X restore 57 164 pd libs_not_loaded_by_default;
+#X text 269 163 <- two libraries to go: tof and iem_tab;
 #X connect 0 0 2 0;
 #X connect 1 0 4 0;
 #X connect 2 0 14 0;