altoslib: Fix freq preference loading

Allocate throw-away freq array to get the class pointer.
Add null-ary AltosFrequency constructor for JSON code.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/altoslib/AltosFrequency.java b/altoslib/AltosFrequency.java
index 6838be8a..dfe33789 100644
--- a/altoslib/AltosFrequency.java
+++ b/altoslib/AltosFrequency.java
@@ -62,4 +62,7 @@ public class AltosFrequency {
 		frequency = f;
 		description = d;
 	}
+	public AltosFrequency() {
+		this(0, null);
+	}
 }