arepl does not show bigints correctly

[Almenon]

see https://news.ycombinator.com/item?id=18412844

x=123456789123456789

shows up as x: 123456789123456780

Also extremely big numbers get converted into infinity and fail to show up at all

[Almenon]

I should switch to using https://github.com/sidorares/json-bigint to parse

[Almenon]

two problems:

1. right now it converts it to a bignumber class... I should probably wait till we get native bignumbers (node 10.4.0).

• I could convert it to a string instead, but I don't want numbers to show as strings

2. there is an exception when converting very large numbers