update the readme

git-svn-id: svn://svn.icculus.org/fs2open@10482 387891d4-d844-0410-90c0-e4c51a9137d3
use the StandardCharsets class

git-svn-id: svn://svn.icculus.org/fs2open@10483 387891d4-d844-0410-90c0-e4c51a9137d3
1) storing a null value in a Properties object causes a NullPointerException, so store the string "null" instead
1a) (this is actually nice because if null values *could* be stored, the installNotNeededCheck would have missed that case and caused them to be reinstalled over and over again)
2) if we end up with an escaped RuntimeException, like in this situation, make sure child items are cancelled properly

git-svn-id: svn://svn.icculus.org/fs2open@10484 387891d4-d844-0410-90c0-e4c51a9137d3