specialized entry to run with mathics

Hacked the main.py file from the Mathics project to
load a file by "<<file.m;", and allow for more
trailing operators to indicate line continuation.
And it also correctly concatenate lines if a line
ends with '\'. Once mathics is installed, run
by "$ python main.py index.all" and the program
is not yet able to load without problem, it reports
something like: "Expression" does not has "is_same".