windows: support Ruby 2.1.0
Merge pull request #213 from myokoym/windows-support-ruby-2-1-0

windows: support Ruby 2.1.0

Patch by Masafumi Yokoyama. Thanks!!!
windows: remove explicit cairo gem dependency

glib2 gem depends on it.
gdk3 windows: bundle hicolor-icon-theme
Set license information to gems
Add 2.1.0 entry
Bump version

2.1.0 ->
2.1.1
    ^
gtk2 windows: link imime module statistic

Reported by OBATA Akio. Thanks!!!
gdk3 windows: link imime module statistic
gtk2 windows: bundle all IM modules
gdk3 windows: bundle all IM modules statistically
gtk2 windows: fix build error
gtk2 windows: add a missing slash

Pointed out by Masafumi Yokoyama. Thanks!!!
poppler: suppress a warning

    lib/poppler.rb:39: warning: assigned but unused variable - micro
poppler: remove needless require

Because poppler no longer depends on gtk2.