spi: Add optional delay around CS transitions
Merge pull request #49 from tessel/km-spi-delay

spi: Add optional delay around CS transitions
Refactored the hw.spi_transfer methods in builtin/tessel

changed unsigned to uint_32t

refacted initTransfer to _performTransfer

updated submodule

removed npm-debug.log
travisplexer: pr-50-arm travis ci test