Make text appear in GUI console, Zip install works.

Move TW zip install code to C++ so that it can use the
ui->functions.
Bring in mincrypt code to fix a crash during signature
checking.
diff --git a/prebuilt/bbinstall.sh b/prebuilt/bbinstall.sh
index c59fec2..2aab969 100755
--- a/prebuilt/bbinstall.sh
+++ b/prebuilt/bbinstall.sh
@@ -1,5 +1,10 @@
 #!/sbin/sh
 
+if [ -f "/sbin/[" ];
+then
+exit
+fi
+
 for cmd in $(/sbin/busybox --list); do
 	/sbin/busybox ln -s /sbin/busybox /sbin/$cmd
 done