merge to resolve multiple pickle security issues (#1728)

* 注释调试if分支

* support pdf url for latex translation

* Merge pull request from GHSA-mvrw-h7rc-22r8

* 注释调试if分支

* Improve objload security

* Update README.md

* support pdf url for latex translation

---------

Co-authored-by: binary-husky <96192199+binary-husky@users.noreply.github.com>
Co-authored-by: binary-husky <qingxu.fu@outlook.com>

* fix import

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Co-authored-by: Longtaotao <longtaotao@bupt.edu.cn>
Co-authored-by: iluem <57590186+Qhaoduoyu@users.noreply.github.com>

toolbox.py

@@ -868,23 +868,6 @@ class ProxyNetworkActivate:
         return
 
 
-def objdump(obj, file="objdump.tmp"):
-    import pickle
-
-    with open(file, "wb+") as f:
-        pickle.dump(obj, f)
-    return
-
-
-def objload(file="objdump.tmp"):
-    import pickle, os
-
-    if not os.path.exists(file):
-        return
-    with open(file, "rb") as f:
-        return pickle.load(f)
-
-
 def Singleton(cls):
     """
     一个单实例装饰器