Feature: case-insensitive enum values

[vlsi]

Currently, enum values are treated as case-sensitive.
I think case-insensitive lookup would make it easier for the end-users to pass the values

[britter]

We think this makes sense. However when we do this, it would break builds that worked around this limitation by defining upper case and lower case parameter values, e.g. values.addAll("AUTO", "auto", "OFF", "off") would not work anymore. Or at least it needs to be considered when implementing this.