libyaml is an optional dep for ruby psych. When missing, it uses
a bundled version of yaml. However, when libyaml is present in
openwrt build, ruby-psych packaging failed with deps not declared.
Now libyaml is configured as a hard dep for ruby-psych.

Also, the tk module was disabled in order to avoid a possible similar
problem if tk+x11 is provided in openwrt build. It was currently not
build because of missing deps.

Other minor changes:
- win32* modules where disabled (avoid err msg, no compile changes)
- Some files where removed in 2.2.x (like gserver.rb). They were already
  not packaged but generates a build warning message. Now removed from install.

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>