targets: zephyr: Update for Zephyr 1.10 which uses CMake-based build. (#2155)

In 1.10, Zephyr RTOS switched to CMake as means to generate application
makefiles. Consequently, drop Makefile, and introduce CMakeLists.txt,
and update master Makefile.zephyr accordingly.

With these changes, take a chance to make following "cosmetic" changes:

1. Make "qemu_x86" board target the default instead of "arduino_101".
Arduino 101 is just one of the boards of many supported by Zephyr
(and thus JerryScript port), while qemu_x86 is something everyone has.

2. Zephyr make target to run QEMU switched from "qemu" to "run".

3. Don't rely that there's zephyr.strip, it's presence is now
board-dependent. The most we can rely on is zephyr.elf.

targets: zephyr: Remove deprecated prj.mdef file.

MDEF files have been deprecated and ignored for few Zephyr releases.

targets: zephyr: Increase main (i.e. interpreter) thread stack size.

qemu_x86 target now has stack guard enabled by default and it trips with
the default stack size. Set it to 2K for now.

targets: zephyr: Makefile.travis: Update for Zephyr 1.10.

Zephyr 1.10 requires SDK 0.9.2 and CMake 3.8.2.

Also, don't hardcode CC path, it depends on a board and choosed
automatically by Zephyr build system.

JerryScript-DCO-1.0-Signed-off-by: Paul Sokolovsky paul.sokolovsky@linaro.org

targets/zephyr/prj.conf

@@ -1,6 +1,8 @@
+CONFIG_BUILD_OUTPUT_BIN=y
 CONFIG_STDOUT_CONSOLE=y
 CONFIG_NEWLIB_LIBC=y
 CONFIG_FLOAT=y
+CONFIG_MAIN_STACK_SIZE=2048
 CONFIG_CONSOLE_HANDLER=y
 CONFIG_CONSOLE_HANDLER_SHELL=y
 CONFIG_ARC_INIT=n