trezorService: Refactoring
More trezorService refactoring

app.js: Split in several functions

ItemStorage: Renamed from DeviceStorage

Transport: Deleted, unnecessary, trezor.js will always be present

DeviceList, deviceService, firmwareService... Documentation
Remove forgotten import
DeviceCtrl: Store per device the setting whether to forget or not a device when it's disconnected.
Firmware: Fixed and improved the workflow. Allow to close the modal.
Firmware: Forget the temporary bootloader device after update success or error.

Now the 'Get started' message appears when update ends.
DeviceList: Do not show a flash error when aborting a hook.
Device: Fix forgetting of a device in bootloader mode.
nav: Remove element excluding BL devices

Conflicted with element structure dictated by Bootstrap.
DeviceList#all(): Do not include devices that are in bootloader mode.
DeviceList#all(): Fixed, features.bootloader_mode might also be undefined.
Devices: Redirect to first device on forget. Nav: Fixed list refreshing.
MainCtrl: Make sure deviceList.count() is always fresh.
firmware: Close bootloader modal after disconnect
DeviceList#_watch(): Poll device immediately.
Sign: Migrated to DeviceList from trezorService
DeviceList: Fixed enumerate pausing and empty features
CSS: Syntax error fixed
Disconnect modal: Text updated to reflect that the setting is not remembered forever now.