Remove EArrayInit as it's no longer needed

According to Steven Schveihoffer (and the code itself), EArrayInit is no longer needed or used.
http://forum.dlang.org/thread/nenooyjciemcmtlkalgo@forum.dlang.org

This is blocking a toString implementation for const, immutable, and inout Nullable!T when T is char, wchar, or dchar, so let's remove it for good.