Increase requirement to PHP 5.4

[clphillips]

Since PHP 5.3 is EOL, and 5.4 will be EOL in September, 2015, it should be safe to make 5.4 the base requirement.

5.4 adds traits, array shortcuts, and removes stupid crap like register_globals.

I agree and namespacing :)

I needed namespacing so I added it and updated the autoloader. If you like my changes I'll submit a pull request (or you can merge them yourself)...

https://github.com/Feathur/minphp/commit/d3af4d3c698bd7dc80432ec6129cf06980ae45bd