added executeAsync() and rollbackAsync() to IProcessComponent

Signed-off-by: Christian Lüthold <biocodr@gmail.com>
implemented new async methods

Signed-off-by: Christian Lüthold <biocodr@gmail.com>
tested new async execution

Signed-off-by: Christian Lüthold <biocodr@gmail.com>
documentation for the new methods added

Signed-off-by: Christian Lüthold <biocodr@gmail.com>