Add line info support. (#2286)

Add line info data to byte, which allows getting a backtrace info directly
from the engine. Snapshots are not supported.

JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com

docs/02.API-REFERENCE.md

@@ -58,6 +58,7 @@ Possible compile time enabled feature types:
  - JERRY_FEATURE_TYPEDARRAY - Typedarray support
  - JERRY_FEATURE_DATE - Date support
  - JERRY_FEATURE_REGEXP - RegExp support
+ - JERRY_FEATURE_LINE_INFO - line info available
 
 ## jerry_parse_opts_t
 
@@ -5434,6 +5435,31 @@ main (void)
 - [jerry_run](#jerry_run)
 - [jerry_vm_exec_stop_callback_t](#jerry_vm_exec_stop_callback_t)
 
+## jerry_get_backtrace
+
+**Summary**
+
+Get backtrace. The backtrace is an array of strings where
+each string contains the position of the corresponding frame.
+The array length is zero if the backtrace is not available.
+
+This function is typically called from native callbacks.
+
+**Prototype**
+
+```c
+jerry_value_t
+jerry_get_backtrace (uint32_t max_depth);
+```
+
+- `max_depth` - backtrace collection stops after reaching this value, 0 = unlimited
+- return value
+  - a new array
+
+**See also**
+
+- [jerry_create_external_function](#jerry_create_external_function)
+
 
 # ArrayBuffer and TypedArray functions