poppler: suppress warnings

    rbpoppler-annotationmarkup.c: In function 'Init_poppler_annotationmarkup':
    rbpoppler-annotationmarkup.c:87:5: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]

    rbpoppler-fontsiter.c: In function 'Init_poppler_fontsiter':
    rbpoppler-fontsiter.c:112:5: warning: ISO C90 forbids mixed declarations and code [-Wdeclaration-after-statement]
poppler: add "-" as word separator
poppler: add "_" as word separator
poppler: update the expected image for Poppler 0.20.3
gtk2 rbgdkdragcontext.c: drop GTK_CHECK_VERSION(2,2,0)
gtk2 rbgdkdraw.c: drop GTK_CHECK_VERSION(2,2,0)
gtk2 rbgdkevent.c: drop GTK_CHECK_VERSION(2,2,0)
gtk2 rbgdkgc.c: drop GTK_CHECK_VERSION(2,2,0)
gtk2 rbgdkkeymap.c: drop GTK_CHECK_VERSION(2,2,0)
gtk2 rbgdkpango.c: drop GTK_CHECK_VERSION(2,2,0)
gtk2 rbgdkpixbuf.c: drop GTK_CHECK_VERSION(2,2,0)
gtk2 rbgdkpixmap.c: drop GTK_CHECK_VERSION(2,2,0)
gtk2 rbgdkproperty.c: drop GTK_CHECK_VERSION(2,2,0)
gtk2 rbgdkscreen.c: drop GTK_CHECK_VERSION(2,2,0)
gtk2 rbgdkselection.c: drop GTK_CHECK_VERSION(2,2,0)
gtk2 rbgdkvisual.c: drop GTK_CHECK_VERSION(2,2,0)
gtk2 rbgdkwindow.c: drop GTK_CHECK_VERSION(2,2,0)
gtk2 rbgdkx11.c: drop GTK_CHECK_VERSION(2,2,0)
Merge pull request #183 from cosmo0920/drop-gtk2.2.0-macro-gdk-part

drop GTK_CHECK_VERSION(2,2,0) macro in gtk2/gdk*.c

Patch by cosmo. Thanks!!!
gtk3: add css_accordion sample