Release candidate 5 for factory firmware

• Default advertisement interval is now 1280 ms + random interval to match apple guidelines.
• URL mode is deprecated and replaced by RAWv2 mode (data format 5).
• Tag has 3 modes: RAWv1, RAWv2, RAWv2_slow.
• Slow mode advertises at 5 * 1285 ms interval to save battery, 6420 ms + 0-10 ms.
• RAWv1 consumes 19 uA at 3 volts, expected runtime is 4.8 years
• RAWv2 consumes 23 uA at 3 volts, expected runtime is 4 years
• RAWv2_slow consumes 14 uA at 3 volts, expected runtime is 6 years
• Tag reboots after NFC read to work around occasional hang after NFC read
• Mode is stored to flash and read from flash after reboot.
• Long press on button "B" enters DFU mode
• Tag boots in RAWv2 mode, and modes are cycled by a short button press.
• Red led blinks on RAWv1 mode and green led blinks on RAWv2 mode.
• The data format 5 / RAWv2 has been in use for over year and is supported by most of the community libraries.
• Power consumption is calculated at 3 V voltage, and life time is estimated at room temperature with a safety factor of 0.8