standalone linux app nearly ready

also made several fixes that apply to the OSX app

ui-macos/git-annex.app/Contents/MacOS/git-annex-webapp

@@ -9,11 +9,17 @@ if [ ! -e "$base/runshell" ]; then
 	exit 1
 fi
 
+# Get absolute path to base, to avoid breakage when things change directories.
+orig="$(pwd)"
+cd "$base"
+base="$(pwd)"
+cd "$orig"
+
 # If this is a standalone app, set a variable that git-annex can use to
 # install itself.
 if [ -e "$base/bin/git-annex" ]; then
-	GIT_ANNEX_OSX_APP_BASE="$base"
-	export GIT_ANNEX_OSX_APP_BASE
+	GIT_ANNEX_APP_BASE="$base"
+	export GIT_ANNEX_APP_BASE
 fi
 
 "$base/runshell" git-annex webapp "$@"