add .gitattributes
rename configure.in to configure.ac
make aclocal happy
autogen.sh: use glibtoolize instead of libtoolize (needed on OSX with homebrew)
remove autogen.sh generated Makefiles from repo
modernize AC_INIT_AUTOMAKE
modify autogen.sh to copy all missing files to directory
add autoconf generated files to repo
comment out non-const accessor to const member
adjust .gitignore
minor fix in pixfmt header