[letterspace] split long line
[extralibs] remove references to typo-krn.lua and related functionality
[letterspace] remove typo-krn.lua
[letterspace] purge redundant locals
[doc] update news
[letterspace] merge luaotfload-extralibs into luaotfload-letterspace
[extralibs] kill luaotfload-extralibs.lua
[letterspace] eliminate some now unnecessary globals
[doc] update news
[doc] remove references to extralibs and typo-krn from manual
[main] adapt initialization
[doc] erase references to typo-krn and extralibs from file graph
[doc] don’t mention mkluatexfontdb.lua in file graph
[status] update file list
[letterspace] move to luaotfload.letterspace namespace
[doc] document letterspacing
Merge pull request #159 from phi-gamma/master

make fontwise letterspacing an official supported feature