New tx layout

[dreautall]

Fixes #22

Quite a big change, needs to be beta-tested first.

Checks to do:

• [x] Adapt page layout
• [x] Detect dynamically what kind of TX is going to be created (when new) -- like webinterface
• [x] Have fixed TX direction for editing TXs (changing is not allowed by FF3)
• [ ] Show only source (destination) account in split transaction for deposit (withdrawal), none for transfer
• [ ] Properly check new page