Hifiberrydsp

- cache program checksum
- dsptoolkit client program now used XML file provided by sigmatcpserver
(required major code cleanup)
- added mute/unmute function
- added samplerate function

- bugfix reading and writing volume levels
- implemented read-prog command

- added more functions to read registers and XML metadata
- added program memory checksum
- TCPServer can now manage the DSP profile
- save/restore DSP data memory on start/stop

- bugfix for SigmaStudio read support

- functionality to upload FIR filter coefficients

- write EEPROM support