Clear blobs in update.

Previously we were just leaking disk space.
adding check for non-empty option parameter at command-line parsing and config-file parsing
changing do_serve to instantiate less things when run in proxy mode - should stop proxy from crashing when the web ui is connected
fixes #1292
Merge branch 'next' of github.com:rethinkdb/rethinkdb into next
Merge branch 'next' into sam_header_cleanup
Merge branch 'sam_header_cleanup' into next
Merge branch 'next' into sam_style_cleanup

Conflicts:
	src/rdb_protocol/pseudo_time.cc
Merge branch 'sam_style_cleanup' into next
Merge branch 'next' into sam_counted_insanity_cleanup
Merge branch 'sam_counted_insanity_cleanup' into next
Merge branch 'next' into blob_leak_fix
adding export/import/dump/restore to the top-level help printout
fixes #1290
fixed options parsing unit tests and added more
fixes #1287
Merge branch 'next' of github.com:rethinkdb/rethinkdb into next
Restored < operator to `counted_t`.
Merge branch 'next' of github.com:rethinkdb/rethinkdb into next
fixing some problems with import error reporting, performance, and interruption; import now requires --force to import a table with rows with identical primary keys