check min. size
typ file: changed wind generator image

Now it's unlikely to be mistaken as an airport symbol.
Revert "open info page at startup, but display it only once for the user"

This reverts commit 2bd3e9676423f0f50513715425b3dcddf4dcfa10.
15min
startDrag() only on the empty homepage
sync with extract-dialog/en/about.html
typ2legend.pl XPM refactoring

A new class Typ2Legend::XPM was created for the XPM parsing code,
together with a new test.
home page link will work on devel installation as well
test json config
add EXTRACT_USAGE
test all *.json files
data update
display context-sensitive help message in left sidebar
function M() will support arrays of message
function M() will support arrays of message
function M() will support arrays of message
link to full screen page instead images
add missing extract usage message for other languages
Merge remote branch 'eserte/master' into world
Typ2Legend::XPM: also support for line XPMs