Misc Export fixes

- Temporarily disable export of base.cue as it causes merge errors at
  the end of compute
- Fixes for JSON export for Scalar and Lists
- Add YAML export
- Removed BOOL and NUMBER support, using JSON for now
- Re-enabled all export tests

Fixes #36

Signed-off-by: Andrea Luzzardi <aluzzardi@gmail.com>

examples/tests/export/json/main.cue

@@ -1,6 +1,31 @@
 package testing
 
-test: #dagger: compute: [
+testScalar: {
+	bool
+
+	#dagger: compute: [
+		{
+			do:  "fetch-container"
+			ref: "alpine"
+		},
+		{
+			do: "exec"
+			args: ["sh", "-c", """
+				echo true > /tmp/out
+				""",
+			]
+			dir: "/"
+		},
+		{
+			do: "export"
+			// Source path in the container
+			source: "/tmp/out"
+			format: "json"
+		},
+	]
+}
+
+testMap: #dagger: compute: [
 	{
 		do:  "fetch-container"
 		ref: "alpine"
@@ -20,3 +45,29 @@ test: #dagger: compute: [
 		format: "json"
 	},
 ]
+
+// FIXME: lists are currently broken
+// testList: {
+//  [...string]
+
+//  #dagger: compute: [
+//   {
+//    do:  "fetch-container"
+//    ref: "alpine"
+//   },
+//   {
+//    do: "exec"
+//    args: ["sh", "-c", """
+//     echo '["milk", "pumpkin pie", "eggs", "juice"]' > /tmp/out
+//     """,
+//    ]
+//    dir: "/"
+//   },
+//   {
+//    do: "export"
+//    // Source path in the container
+//    source: "/tmp/out"
+//    format: "json"
+//   },
+//  ]
+// }