Adding Update Offline Wallet Functionality

This allows you to update the offline wallet with the latest
addresses, balance, history, and labels from Watch-only.
Add ability to set fee and change address in csv

format:
fee, (fee in BTC)
change, (change address)

if there are more than one rows with the change or fee on it, it will
become the one on the bottom. (it will overwrite the previous one)
CSV: Show erroneous addresses in warning window.

This will show all erroneous addresses given in a CSV import to the user
before returning out of the function.

Referenced issue: (from the forums, by PBmining)
https://bitcointalk.org/index.php?topic=100502.msg5325935#msg5325935

This branch will implement the fees and change address deciding ability
for csv imports along with the error notifications.
Fixed change address in csv
Is_valid assert wasn't displaying anything.

Fixed it with a message.
Changed CSV History export to UTF-8 labels

Japanese characters were causing history to be aborted halfway through
export, so by changing the label to UTF-8 I was able to export the CSV
properly.
Offline Update + CSV fee/changeaddress

pulled in the new commits from spesmilo master and rebased my personal
functions on to it.