Basic file reader/writer

Signed-off-by: Jonas Kalderstam <jonas@kalderstam.se>
OPML classes

Signed-off-by: Jonas Kalderstam <jonas@kalderstam.se>
OMPL import/export fixes #5

Signed-off-by: Jonas Kalderstam <jonas@kalderstam.se>
Merge branch 'export_feature'