Use external handlers in tizenrt-artik05x target (#1822)

This patch includes followings:
- Use external handlers in jerry-ext.
- Make jerry_main similar to other ports. (including options)
- Merge jerry_port.c into jerry_main.c
  jerry_port is clearly out of jerry-core.

This patch not included following:
- Use jerry-libm, instead of system libm.
  It is already included.
  We choose to use jerry-libm since the result of cube-3d sunspider was inaccurate
  when using NuttX libm.
- Correct setjmp/longjmp implementation.
  I tried to bring the source from NuttX port.
  Unfortunately it does not work in tizenrt-artik05x as it is.
  I will take a closer look the code and make sure it works.

JerryScript-DCO-1.0-Signed-off-by: Sanggyu Lee sg5.lee@samsung.com

targets/tizenrt-artik05x/apps/jerryscript/Makefile

@@ -81,6 +81,7 @@ PRIORITY = $(CONFIG_JERRYSCRIPT_PRIORITY)
 STACKSIZE = $(CONFIG_JERRYSCRIPT_STACKSIZE)
 CFLAGS += -std=c99 -DJERRY_NDEBUG -DJERRY_JS_PARSER '-DCONFIG_MEM_HEAP_AREA_SIZE=$(CONFIG_JERRYSCRIPT_HEAPSIZE)'
 CFLAGS += -I$(ROOT_DIR)/ $(shell find $(ROOT_DIR)/jerryscript/jerry-core -type d | sed -r -e 's/^/-I/g')
+CFLAGS += -I$(ROOT_DIR)/jerryscript/jerry-ext/include
 
 ifeq ($(CONFIG_JERRYSCRIPT_MEM_STATS),y)
 	CFLAGS += -DJMEM_STATS
@@ -100,7 +101,7 @@ LINKLIBS=$(EXTRA_LIBS)
 
 
 ASRCS =
-CSRCS = jerry_port.c
+CSRCS =
 MAINSRC = jerry_main.c
 
 AOBJS = $(ASRCS:.S=$(OBJEXT))