`fluid.transients`,`fluid.transientslice`, `fluid.buftransients` and`fluid.buftransientslice` all crash when changing parameters.

[MattS6464]

fluid.transients,fluid.transientslice, fluid.buftransients andfluid.buftransientslice all crash when the order, blocksize or padsize parameters are changed in their help files.
To recreate, open the one of their help files, turn on audio and then change one of the three parameters. For the buffer versions of the objects, change one of the parameters and then bang an output.
This occurs on a debug build.

[AlexHarker]

@MattS6464 Please could you and @lewardo give some crash logs or more data as to where the crashes happen (assuming that these still happen with the outlined threading fix). It's quite possible that this is a separate issue(s) but this one needs further info to locate it more precisely.