Provide details about the security changes in p2 and the impact on PDE (#95)

https://github.com/eclipse-equinox/p2/issues/230
https://github.com/eclipse-equinox/p2/issues/235
https://github.com/eclipse-equinox/p2/pull/245
https://github.com/eclipse-equinox/p2/pull/248
8 files changed