Refactor the generator scripts for unicode tables (#1623)

Extract the source code generator methods into a separated `unicode_c_source.py` script.
Fix the generator scripts to make them compatible with both Python2 and Python3.
Remove pylint warnings.

JerryScript-DCO-1.0-Signed-off-by: Robert Sipka rsipka.uszeged@partner.samsung.com

jerry-core/lit/lit-unicode-ranges.inc.h

@@ -11,11 +11,11 @@
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
- *
- * This file is automatically generated by the unicode_ranges.py script
- * from UnicodeData-3.0.0.txt. Do not edit!
  */
 
+/* This file is automatically generated by the unicode_ranges.py script
+ * from UnicodeData-3.0.0.txt. Do not edit! */
+
 /**
  * Character interval starting points for the unicode letters.
  *
@@ -180,4 +180,3 @@ static const uint16_t jerry_unicode_separator_chars[] JERRY_CONST_DATA =
 {
   0x1680, 0x180e, 0x202f, 0x205f, 0x3000
 };
-