Limit batch size on +translate pages to 50

[Данило Шеган]

At the moment, we get a lot of timeouts on POFile:+translate pages when people use batch sizes of 300, 150, 100 or 90. We are not yet ready to handle that many translations on a page, so we should limit it to a value we can handle, like 50.

We know what further optimizations we can do to render this page even faster, but it will take more time, and timeouts with big batch sizes do not help because they hide other, perhaps more important problems.

OOPS-1289EA25, OOPS-1289EA48, OOPS-1289EA56, OOPS-1289EA67, OOPS-1289EA71

[Henning Eggers (henninge)]

Fixed n devel 8887.