Upgrade the dependency on Bouncy Castle (1.46 -> 1.49)

Hi,

Could you please update the dependency on Bouncy Castle ? The new versions of Bouncy Castle do not preserve the binary compatibility and this is causing issues when components using different versions of Bouncy Castle are mixed together. This pull request updates the dependency to the latest release of Bouncy Castle. This is a minimal upgrade to compile and run the tests, there are some deprecations left.

Thank you.