Fixed wrong usage when invalid option was specified.
Fix panic with broken file.
Add broken file test for grep
go fmt
Import "code.google.com/p/go.text/encoding" instead of "code.google.com/p/mahonia".

mahonia is deprecated on 2013-12-26.
https://code.google.com/p/mahonia/source/detail?r=937b608805fa1ef555f3247a411a967ca3fa3466
Merge branch 'fix-panic' into add-iso-2022-jp-support
Add support for ISO-2022-JP
Make go gettable.