poppler: backport event sub classes from gtk2/

Github: #180
Merge pull request #211 from cosmo0920/poppler-subclass-backport

poppler: backport event sub classes from gtk2/

Patch by cosmo. Thanks!!!
poppler: revert exporting PopplerAction convert functions on Windows

Because nobody uses them for now. We will export them when someone
request them.
poppler: fix argument name

It is an action not an event.
poppler: revert conversion function name rules

rval2XXX ->
XXX_from_ruby_object

XXX2rval ->
ruby_object_from_XXX

Because XXX_from_YYY naming rules are used in Ruby/Poppler.
poppler: remove "event" word and use "action" instead

Because they are "action" not "event".
poppler: fix indent
poppler: fix a typo

rb_cPopplerActionRend tion ->
rb_cPopplerActionRendition
                     +
poppler: allign continuous line marks
poppler: fix indent
poppler: allign continuous line marks
poppler: use "URI" for URI notation

Because URI is the normal notation.
travis: remove needless allow_failures

Because Ruby-GNOME2 packages are ready to run on Ruby 2.1.0. Thanks!!!!!
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