* lib/review/compiler.rb, lib/review/htmlbuilder.rb,   lib/review/latexbuilder.rb: move core tag @<icon> to   compiler.rb. * lib/review/topbuilder.rb: supports same tags with other builders.
* lib/review/compiler.rb, lib/review/htmlbuilder.rb,
  lib/review/latexbuilder.rb: move core tag @<icon> to
  compiler.rb.
* lib/review/topbuilder.rb: supports same tags with other builders.

krororo/review,krororo/review,kdmsnr/review,krororo/review,suzuki/review,orangain/review,masawada/review,takahashim/review,kuad9/review_study,orangain/review,kmuto/review,kmuto/review,murashitas/review,suzuki/review,kuad9/review_study,takahashim/review,masawada/review,murashitas/review,kmuto/review