Fix several issues for Linux around casting SDKManager to concrete class: mostly with reading devices.xml which Unix does not support. Migrated ISDKManager#getMinimumSupportedSBSv2Version() to API. Can now import and create Symbian projects.

source.uidesigner.jar = src/
output.uidesigner.jar = bin/
bin.includes = plugin.xml,\
               uidesigner.jar,\
               META-INF/MANIFEST.MF,\
               plugin.properties,\
               icons/