vm.txt: paraphrase
Add info about support *.docx in app libreOffice
Remove word "Mozilla" in subtopics about "Thunderbird"
Update information about "Pidgin"
Remove numbers before all level 4 topics: "==== topic ===="

Add "[float]" before all 4 level topics:
   now subtopics look more readable
   for example it was "61.1.1. blabla" and now it become "blabla"
   but it is still looks like subtopic. All difference is that now
   there is no numbers before topic name.

Conflicts:
	maint/index.txt
	services/index.txt
	system-server/index.txt