Feature request: Clear file buffer

[adamgarbo]

Hi @PaulZC,

As discussed earlier, it could be useful for the u-blox library to include functionality allowing the user to clear the file buffer as needed. This could be helpful when wanting to enable logging, but not immediately process the data, or to clear the buffer when starting/stopping other tasks. Adding a command to reset the value of the getMaxFileBufferAvail() could also be a nice related feature.

Cheers,
Adam