poppler: add not implemented poppler subclass and its accessor

* ActionRendition and ActionOCGState were not implemented.

* implement additional accessor
poppler rbpoppler.c: Drop Poppler < 0.12 support
poppler rbpoppler-fonts-iter.c: Drop Poppler < 0.12 support
poppler rbpoppler-annotation-text.c: Drop Poppler < 0.12 support
poppler rbpoppler-font-info.c: Drop poppler < 0.12 support
poppler extconf.rb: require Poppler 0.12 or later
poppler: require Poppler 0.12 or later

GitHub: fix #212
poppler: add missing Poppler version check
poppler: use correct JavaScript notation

Javascript ->
JavaScript
    ^
poppler: add a missing POPPLER_ACTION_JAVASCRIPT definition

We need tests for actions...
poppler: fix wrong parent class

We need tests for actions...
glib2 windows: bump versions

glib2: 2.38.2
gnutls: 3.2.7
glib-networking: 2.38.2
glib2 windows: fix a cross compiling error

The error occurred in GnuTLS by MinGW-w64 3.0.0 and GCC 4.8.2.

    ../../gl/string.h:1002:1: error: expected unqualified-id before 'char'
     _GL_FUNCDECL_SYS (strtok_r, char *,
     ^
    ../../gl/string.h:1002:1: error: expected ')' before 'char'
    ../../gl/string.h:1002:1: error: expected ')' before 'char'
    ../../gl/string.h:1002:1: error: expected initializer before 'char'
    make[4]: *** [ex-cxx.o] Error 1

The error fixed, but I don't understand the reason of the problem...

TODO: libglib-2.0-0.dll depends on the libralies but they are not found.

    * libgcc_s_sjlj-1.dll
    * libwinpthread-1.dll
glib2 windows: remove a removed configure argument
glib2 windows: disable GnuTLS's C++ supported build

Because m4 for configure of gnulib bundled in GnuTLS checks only
strtok_r() availability only in C. It doesn't check in C++. So needed
`#undef strtok_r` isn't executed in gl/string.h.
Remove an unused variable
glib2 windows: add more $(EXEEXT) for GLib 2.38.2
glib2 windows: bundle DLLs provided by GCC
gi windows: update GLib
glib2 windows: fix a typo...

buildler ->
build er
     -