And, reluctantly, default to bitcoind style.
"It's wrong to be right too soon."
Suggested-by: @cdecker
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
New codes: FUND_MAX_EXCEEDED, FUND_CANNOT_AFFORD, FUND_DUST_LIMIT_UNMET.
The error message "Cannot afford fee" was not exactly correct because
it would also occur if the amount requested could not be afforded. So
I changed it to the more generic "Cannot afford transaction".
Other things:
* Fixed off-by-one satoshi in fundchannel manpage.
* Changed 'arror' to 'error' because we are not pirates.