Update todo list based on a quick scan of the Windows makefiles
for 1.4.x HEAD (more likely to be correct than trunk perhaps?)

Delete todo about describing nmake usage, as the doc added in r1517944
should be a big help.


git-svn-id: https://svn.apache.org/repos/asf/apr/apr/trunk@1517968 13f79535-47bb-0310-9956-ffa450edef68