translate: refactor the loading loop into iterator logic
translate: refactor the loading loop into iterator logic

The previous code would read the whole .po file into memory, and then
try to examine the lines. Now, we keep a transparent iterator on the
file object and parse line-by-line (with the pythonic readahead buffer).

It seems to be clearly faster.

xrg/openerp-server,xrg/openerp-server