* initial draft
* working alternative without using i32 id's
* EspSpiDevice + SpiDriverMaster / no global statics
* start splitting implementation in spi & spi_pool
* impl SpiDevice for EspSpiDevice
* spi2_pool draft (spi with software based cs)
* pre master fetch up
* Driver accepts Optional DMA channel + fetch master
* replaced: std with core, mutex with hal's cs
* replaced HashMap with Array
* merged spi2 into spi
* clean up
* replace std with core
* updated loopback example, spi takes dma directly
* moved criticalsection guard out of spi to spi_pool
* added paragraph to the release.md
* rm fn to add / rm device from bus or update config
* rm stored config from EspSpiDevice
* fmt'd
* grammer + changelog update
* implements inverted chipselect for spi.rs #119
* device with optional cs + guarded soft_cs wrapper
* fmt'd
* add pre / post cs delay functionality for wrapper
* no bus.finish for dev with no cs. partial fix#99
* spi driver renaming
* updated naming + locking with &mut SpiDeviceDriver
* updated naming + locking with &mut SpiDeviceDriver
* clean up
* updated CHANGELOG
