indexing improvements (1.3.0)

[ultrasaurus]

• require UTF8 files -- "nice" error checking required scanning the whole file, which was resource intensive, now we just preflight that with a script (script/makeutf8.sh), rather than doing lots of error checking on import
• no longer index at app startup:
  • rake import recommended
  • experimental web ui export INDEX_APP=enable to access /index/reindex
• performance improvements for indexing
• some code refactoring to improve readability