firmware, software: change revision format from revX to revXN. Until now, the firmware and software did not know the specific board variant. This doesn't let us work around board bugs.

applet.i2c_master: require revC+. The I2CPadsWrapper hack was horrible to use even when it worked. I can't in good conscience recommenda anyone with a revA/B do that, so let's get rid of it.

device.hardware: add pull set support.

firmware: add pull get/set support.

firmware: persist voltage limit on writes, not reads. Oops... this would have written the EEPROM on each `glasgow voltage` invocation.

applet: add required_revision field.

applet.jtag: enumerate-ir: make more robust to missing DRs. A missing DR is a DR that leaves TDO unconnected when it is selected.

applet.jtag_mips: update the lists of tested configurations.

applet.jtag: enumerate-ir: handle incorrect TAP selection.

applet.jtag: reset TAP chain before selecting a TAP. Selecting a TAP requires reading IDCODE/BYPASS from DR, which means that a TAP chain reset was a precondition for select_tap(), but this wasn't intended or documented. The current design requires a reset, so just add that. Since all derived applets want to select a TAP, remove the TAP reset via TMS from run(); however, keep TAP reset via TRST#, because that enables the TRST# driver.