update checksums of sdl2* packages
package sdl2_net: fix test program build
add package qwt-qt4: builds qwt using qt4
package qwt-qt4: use qwt metadata
package qwt-qt4: rename to qwt_qt4
package qwt_qt4: fix for crlf in patch
package sdl2_net: fix dependency on sdl --> sdl2