Add the new test suite.

This test suite has been in use for a long time now, in place of the obsolete and unmanageable testparser.py and testfuncs.py. It verifies the complete optimizer output to stdout and stderr, to ensure that the output matches the expectations.

See unit_tests/README.txt for more info.

unit_tests/regression.suite/cast-list2xxx.lsl

@@ -0,0 +1,29 @@
+default{timer(){
+
+list L = llDeleteSubList(llGetPhysicsMaterial(), 0, 99999)
+         + [0.9999997, 0.000111222, 2, 2147483647];
+
+// this returns 1, but llList2Integer returns 0
+integer a = (integer)llList2String(L, 0);
+
+// this returns 0.000111, but llList2Float returns 0.000111222
+float b = (float)llList2String(L, 1);
+
+// test consistency
+string c = (string)llList2String(L, 0);
+
+// this returns (key)"2", but llList2Key returns (key)""
+key d = (key)llList2String(L, 2);
+
+// same as above, the typecast is implicit
+key e = llList2String(L, 2);
+
+// this returns 0, but llList2Float would return 0.000111222
+float f = (float)llList2Integer(L, 1);
+
+// this returns -2147483648, but llList2Integer returns 2147483647
+integer g = (integer)llList2Float(L, 3);
+
+llParticleSystem([a,b,c,d,e]);
+
+}}