5.5.1: Initialise flag for all bulbs (#168)

* Initialise flag for all bulbs

* Bump version

Allow transition turn off

Contribution by @lwis

Re-add supported features

Re-add supported features (#158, @lwis)

Move timeout to I/O API

Move timeout to I/O API (#155, @tazle)

Revert GU10 fix, add tests and add debug file

#146 (@ggravlingen)
#148 (@Lakitna)
#151 (@Lakitna)

GU10 support and lamp value validation

#139 (@Lakitna)
#140 (@Lakitna)
#141 (@ggravlingen)

Various fixes

• Adding constants (#126, #129, #130, @ggravlingen)
• Improve functionality around lamp value ranges (#134, @Lakitna)
• PSK handling clarification (#136, @Lakitna)
• Libcoap observer timeout fix (#137, @Lakitna)

Improve psk handling in examples

#118 (@ggravlingen)

Clean up API factories

Clean up API factories #121 (@lwis)

Add transition_time to more methods

Add transition_time to more methods (#120) @jurriaan