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.tests.jar = src/
output.tests.jar = bin/
bin.includes = plugin.xml,\
               META-INF/,\
               tests.jar,\
               data/