Refactoring and bug fixes

[mochizk]

This pull request refactors code base and fix some bugs.

Refactoring :

• Use new instead of malloc
• Use exceptions where it makes code more simple
• Remove preprocessor condition for support of older version like #if GS_COMPATIBILITY_SUPPORT_3_5

Bug fix :

• Fix memory leak
• Add missing error handling

[knonomura]

That's excellent.
Thank you very much for your PR.
I will check it.

[knonomura]

Sorry for late reply.

I checked your source code.

I understand your modification includes mainly improvement for memory management and error handling,
As it is very useful, I will merge it.

As there are some old source code, I will update them later.

Let me confirm one thing.
I understand you change from strdup() to Util::strdup() with new intead of malloc.
As one strdup() remains on line 2097 in gstype_js_v8.i file, I will change it to Util::strdup().
Is it correct ?

[mochizk]

Thank you for checking the code.

As one strdup() remains on line 2097 in gstype_js_v8.i file, I will change it to Util::strdup().
Is it correct ?

Yes, it is correct. I overlooked it.