viewer: Add JSON interface to searcher.
viewer: Add JSON interface to searcher.

Example usage:

    curl -s 'http://HOST/api/v1/search.json?q=tumblr' | jq '[.results[].domain]'

Frogging101/ArchiveBot,emijrp/ArchiveBot,JesseWeinstein/ArchiveBot,falconkirtaran/ArchiveBot,Asparagirl/ArchiveBot,emijrp/ArchiveBot,falconkirtaran/ArchiveBot,ArchiveTeam/ArchiveBot,Asparagirl/ArchiveBot,ArchiveTeam/ArchiveBot,ArchiveTeam/ArchiveBot,JesseWeinstein/ArchiveBot,Asparagirl/ArchiveBot,JesseWeinstein/ArchiveBot,Frogging101/ArchiveBot,emijrp/ArchiveBot,JesseWeinstein/ArchiveBot,emijrp/ArchiveBot,falconkirtaran/ArchiveBot,Frogging101/ArchiveBot,falconkirtaran/ArchiveBot,Asparagirl/ArchiveBot,Frogging101/ArchiveBot,Frogging101/ArchiveBot,Asparagirl/ArchiveBot,emijrp/ArchiveBot,JesseWeinstein/ArchiveBot,ArchiveTeam/ArchiveBot,falconkirtaran/ArchiveBot,ArchiveTeam/ArchiveBot