Updates to 0.91-dev branch: (just pushed)

I have drastically reduced the tracking and handling of zero-conf transactions. This solves 80% of the speed issues using Armory with wallets with 10k+ addresses. I now run with 30k addresses and it runs fine, although it freezes for about 1-3 sec after every new block. Better than 10-15 sec, though (which was causing inter-thread timeouts). I will be working on the per-block scanning ops to reduce it even further (Armory code base should be able to handle 1mil+ addresses, I just haven't optimized the operations to do it)
Updated "Send Bitcoins" dialog, with wallet selection directly in the dialog. Coin control still works, though the interface updates for that broke. Fixing that soon.
Added paranoid-extension of address chains and logging of multipliers. All address chain extensions are now performed twice and answers are compared to make sure it's consistent. Additionally, the final multiplier/exponent applied is logged.
There are still situations where an unclean shutdown will induce a rescan. I have further reduced those situations, though it's not perfect. I will see if the operations are efficient enough to make more reliable.
armoryd.py updates -- a bunch of functions that broke in the update to 0.90 have been fixed. Most importantly, "listtransactions" and "getledger" now work. CircusPeanut is working on building a better test environment for it to improve the reliability.
Updated leveldb block size to 32kb. This seems to improve scan speed on Linux/Mac, without breaking build speed on Windows. Be sure to --rebuild if you want the benefits of the new block size.