Adding authors file.
add to layer only those features which are not already added
fire also 'exception' event, not only deprecated 'loadexception'
Merge commit '1d2bf10' into antenas
do not hide popup when feature not visible on map
Merge commit '78312aa' into antenas
merged in code from antenas project
Merge branch 'master' of https://github.com/lindsejs/geoext
base GeoExt.data.FeatureStore on groupingstore instead of plain store