avr32: work-in-progress

committed so as to ease cooperation and to let it be improved
over time.

So far it supports:
- halt/resume
- registers inspection
- memory inspection/modification

I'm still getting up to speed with OpenOCD internals and AVR32 so code is a little
bit messy and I'd appreciate any feedback.

src/target/target.c

@@ -70,6 +70,7 @@ extern struct target_type mips_m4k_target;
 extern struct target_type avr_target;
 extern struct target_type dsp563xx_target;
 extern struct target_type testee_target;
+extern struct target_type avr32_ap7k_target;
 
 static struct target_type *target_types[] =
 {
@@ -90,6 +91,7 @@ static struct target_type *target_types[] =
 	&avr_target,
 	&dsp563xx_target,
 	&testee_target,
+	&avr32_ap7k_target,
 	NULL,
 };