Add missing trig functions and barebones test

tests/all.test

@@ -409,6 +409,18 @@ null
 [2,4,4,4,5,5,7,9]
 2
 
+# Should write a test that calls the -lm function from C to check
+# that they match the corresponding jq functions.  However, there's so
+# little template code standing between that it suffices to test a
+# handful of these.  The results were checked by eye against bc(1).
+[.[]|cos]
+[.1,.2,.3,.4,.5,.6]
+[0.9950041652780258,0.9800665778412416,0.955336489125606,0.9210609940028851,0.8775825618903728,0.8253356149096783]
+
+[.[]|sin]
+[.1,.2,.3,.4,.5,.6]
+[0.09983341664682815,0.19866933079506122,0.29552020666133955,0.3894183423086505,0.479425538604203,0.5646424733950354]
+
 def f(x): x | x; f([.], . + [42])
 [1,2,3]
 [[[1,2,3]]]