Feature/control individual raw channels

[ShuzzDE]

This basically wraps up two changes in the way this library works without breaking backwards compatibility (badly).

First off, for HSV commands, the Library will only change the channels relevant to the current mode of operation set in the controller, i.e. when controller is setup to work in RGBCW mode, the WW channel will not be affected by sending an HSV-based command.

Second, the library is now able to accept RAW fade commands with individual channels set to -1. These channels will not be changed during fading. This is done by using the current values for those channels when the animation starts execution.

Together with minor changes in the firmware (see PR in esp_rgbww_firmware project), these features will allow for individual control of unused channels, enabling e.g. a single controller to run an RGB LED strip with HSV commands for ambient lighting and two additional single-color strips for lighting up sideboards, shelves or the like.

[aneeshnair123]

hi do you have few more examples of how to use the hsv transition .