Updated translation tips.
Use 'make en', 'make ru', etc. for a single language, and 'make' or 'make all' for all languages at once.
Conflicts: Makefile ru/preface.txt
translation is fixed. The regression of the change is that older versions of AsciiDoc are not directly supported now, manual intervention in lang-$(LANG).conf is required for that.
Thanks to Jerry Jacobs for testing it.
It was getting too big. Also, the chapter on shortcomings is now an appendix. I like having the last chapter end with a section related to the opening sentence of the preface.
Added filter-branch section.
Fixed minor typo reported by Richard Albury.
Minor edits and corrections