firmware docs 0.4.5

[m-mcgowan]

Checklist of all the changes to be doc'ed for the 0.4.5 release:

• STARTUP() macro
• how to contribute to firmware
  • firmware API tests, unit tests, docs, HAL/dynalib rules
• TCPClient.remoteIP
• UDP.setBuffer/sendPacket/receivePacket - implementation of dynamically allocated UDP buffers device-os#452
• Static IP support - static IP support device-os#451
• System Events - https://github.com/spark/firmware/issues/279
• Servo.trim() - servo trim device-os#575
• SecurityCipher param on WiFi.setCredentials() - https://github.com/spark/firmware/issues/574
• UDP multicast join - Added support for UDP multicast device-os#573
• Time.timeStr/format/setFormat/getFormat - Time.timeStr() formatting device-os#572
• SPI.setClockSpeed/setDividerReference - SPI.setClockSpeed/setClockDividerReference device-os#570
• WiFi.scan - https://github.com/spark/firmware/issues/567
• Clarify System.sleep(60); behavior - wifi/cloud state is restored to what it was at the time of sleeping. https://github.com/spark/firmware/issues/480
• Spark.connected() et al. to Particle.connected()

[kennethlimcp]

@m-mcgowan while you are at this,

we have some stale ones like:

• Updates for V0.4.0 firmware #35
• Add Spark.unsubscribe() to the docs #80

Will you be able to work on them as well?