`enumerate` does not obey the `start=` parameter

[halloleo]

When I run in Transcrypt:

for i, c in enumerate(['a', 'b', 'c'], start=1):
    print(I, c)

I get the output:

0 a
1 b
2 c

while CPython gives me the expected:

1 a
2 b
3 c

[JennaSys]

I just created a PR that adds this argument to the Transcrypt version.