compatibility with solc 0.6.6

[mesozoic-technology]

No description provided.

[brianmcmichael]

I noticed that string and bytes32 are not compatible in 0.5.x-0.6.x the same way they that they were back in 0.4.x. name and symbol are defined in the specification as meant to return string, but DS-Token returns a bytes32 for those fields.

If DS-Token is going to be updated for 0.6.x, the name and symbol fields should probably also be updated to spec so that they are readable by newer integrations.