This changes the parameters of dhcpserver_start.
Besides that, dhcpserver_start should only be called after user_init has
finished, else the call sdk_system_get_netif(SOFTAP_IF) will return NULL.
Original work by @ourairquality
* Sysparam threadsafe and SPI access
* Sysparam test cases
* Fix for negative int8
* Sysparam getting bool without memory allocation. Bool tests.
* SPI flash refactoring.
* Extract common spiflash.c into core.
* Use spiflash.c in sysparam.
* Use memcpy in spiflash.c insted of hand-written version.
* Tests for spiflash.c
* Get testing system by projectgus working with master HEAD
* Fix running dual test. Add basic wifi test
* Moved spiff test to a test case. Reset retries in test runner
* Add timers test case
* test_runner: List test cases and run individual test cases
* Add README for tests
* Update README.md
* Code clean-up
* Python3.4 support. README.md update
