Add spk_base.[ch]. (dm)
The Alva braille driver shouldn't reference the global braille display structure. (dm)
Move some functions into spk_base.[ch] (from spk.[ch]). (dm)
Fix the install directory for documentation. (dm)

autoconf appends PACKAGE_TARNAME if set (which we just started to do).
Remove the .gitignore files from the tar file. (dm)