For a watch-only wallet, previously a superfluous dummy "Tap to show"
box was shown.
For a has no seed stored (but not watch-only) wallet (e.g. bip39/xprv/imported_privkeys),
the "show seed" option was there and it raised an uncaught exception.
- Moved the coloring logic (address_colors) from tx_dialog.py to a new file electrum/gui/kivy/util.py
- Added background_color to <RefLabel> in main.kv
- Calling address_colors in the initialization of AddressPopup and setting the foreground and background color
Code cleanup spaces
Code cleanup spaces
Fixed typo