Consider using the PSR-4 autoloader

[peter279k]

As title, it seems that this class still uses the classmap approach to load the Browser class in composer.json.

I think we can consider using the PSR-4 autoloader and the advantages are as follows:

• The PSR-4 approach will have the namespace and it can avoid the class name collision.

Once this issue is accepted, I can help this issue :).

[cbschuld]

@peter279k - I am completely fine with this; we could issue a 2.x version that has this breaking change for those importing it w/ the classmap model

[peter279k]

@cbschuld, thanks for your reply and concern.

I think we can mark the 2.x milestone for this issue and it can let us know that it will be the psr-4 compliant autoloader since the package version is 2.x.