Re: [boost] [lexical_cast] doc update

I'm going to commit to HEAD two new sections 'Frequently Asked Questions' and 'References' and also update 'Changes' section.

I suggest also mentioning the problem with [u]int8_t casting _to_ a string. Suggested wording (if after the FAQ about the opposite conversion): Q: What does lexical_cast<string> of an int8_t or uint8_t not do what I expect? A: As above, note that int8_t and uint8_t are actually chars and are formatted as such. To avoid this, cast to an integer type first: lexical_cast<string>(static_cast<int>(n)). Following are some minor edits to your text: Q: Why does lexical_cast<int8_t>("127") throw bad_lexical_cast? commitee --> committee greate --> great Phil.