bump version 0.10.91
fixes load_text
fixes pinyin_save
fixes feed_file
check return values
add asserts
fixes table info load
fixes memory leaks
fixes memory leaks
fixes validate_bigram
fixes berkeley db calls
fixes lookups
Revert "bump version 0.10.91"

This reverts commit 959bfefcb2a7829231b207c34ab76353f4ad41e5.
bump version 0.9.93