Ignore hidden folder (e.g. .git folder)

[marcolussetti]

This addresses #26 which I think is very nice for those who want to keep the photos and metadata in their own Git repository.

[tmountain]

This should be merged because a .git folder can cause a recursive situation to occur where expose never finishes...

[tmountain]

I applied this manually and can confirm it fixes the recursion bug when using git.

[krupan]

I strongly agree this is needed. This might be a better way to do it (puts it in the same place that directories starting wtih _ are handled/ignored):

diff --git a/expose.sh b/expose.sh
index 3aa8d3d..80ac6f5 100755
--- a/expose.sh
+++ b/expose.sh
@@ -239,7 +239,7 @@ do
        nav_name+=("$node_name")
        nav_depth+=("$node_depth")
        nav_type+=("$node_type")
-done < <(find "$topdir" -type d ! -path "$topdir*/_*" | sort)
+done < <(find "$topdir" -type d ! -path "$topdir*/_*" ! -path "$topdir*/.*" | sort)
 
 # re-create directory structure
 mkdir -p "$topdir/_site"