Added arduino-nano to BOARD_INSUFFICIENT_MEMORY/BOARD_BLACKLIST following suit
of how arduino-uno is marked, as arduino-nano is mostly an Uno in a different
form factor.
The unification of a bigger stack for the atmega platforms
makes some boards to not have enough memory to provide
the big stack plus the application code.
It is possible though, to override the stack size to a
smaller amount if running the test is necessary.
As discussed in #2725, this commit renames a number of stacksize constants to
better convey their intended usage. In addition, constants for thread priority
are given a `THREAD_` prefix. Changes are:
* KERNEL_CONF_STACKSIZE_PRINTF renamed to THREAD_EXTRA_STACKSIZE_PRINTF
* KERNEL_CONF_STACKSIZE_DEFAULT renamed to THREAD_STACKSIZE_DEFAULT
* KERNEL_CONF_STACKSIZE_IDLE renamed to THREAD_STACKSIZE_IDLE
* KERNEL_CONF_STACKSIZE_MAIN renamed to THREAD_STACKSIZE_MAIN
* Move thread stacksizes from kernel.h to thread.h, since the prefix changed
* PRIORITY_MIN renamed to THREAD_PRIORITY_MIN
* PRIORITY_IDLE renamed to THREAD_PRIORITY_IDLE
* PRIORITY_MAIN renamed to THREAD_PRIORITY_MAIN
* Move thread priorities from kernel.h to thread.h since the prefix has changed
* MINIMUM_STACK_SIZE renamed to THREAD_STACKSIZE_MINIMUM for consistency
* I used pexpect instead of when expect script was not working expect, since
TCL confuses me
* I deleted the thread_exit test since it was completely invalid
