[Po4a-devel]Assorted documentation tweaks

I have been reading the documentation further to understand better how the various Perl modules fit together and this lead me to do some extra tweaks along the way. So here they are... Changelog: * doc/po4a.7.pod lib/Locale/Po4a/TransTractor.pm Francois Gouget <fgouget(a)free.fr&gt; Assorted documentation tweaks and spelling fixes. -- Francois Gouget fgouget(a)free.fr http://fgouget.free.fr/ Any sufficiently advanced Operating System is indistinguishable from Linux