all decoders: introduce a reset() method Move initialization code of protocol decoders from the constructor to a new reset() helper method. The libsigrokdecode backend could run this method several times to clear the decoder's internal state, before new data from another acquisition gets fed to decode() calls.
Add srd_inst_initial_pins_set_all() and support code. This allows frontends to set the assumed initial pins (i.e., the assumed state of the pins before the first sample of a capture) to user-specified values. The assumed initial pins can be either low, or high, or "use same value as the first sample of the capture". The special self.initial_pins decoder attribute is now removed.