Update symlink (mage to mgear) in demo zone.

diff --git a/demo/mage.mk b/demo/mage.mk
deleted file mode 120000 (symlink)
index d428552..0000000
--- a/demo/mage.mk
+++ /dev/null
@@ -1 +0,0 @@
-../mage.mk
\ No newline at end of file

diff --git a/demo/mgear.mk b/demo/mgear.mk
new file mode 120000 (symlink)
index 0000000..2765d5b
--- /dev/null
+++ b/demo/mgear.mk
@@ -0,0 +1 @@
+../mgear.mk
\ No newline at end of file