Fix issue when a LP have a .hex with several areas

Merge pull request #137 from LedgerHQ/fix_missing_import_load_app

Fix missing import in loadApp.py

Merge pull request #136 from LedgerHQ/tdj/add_error_codes

Add detailed descriptions for some error codes to ease debug.

Merge pull request #135 from LedgerHQ/xch/fix-loadApp-return-code

loadApp.py: Fix return code

Merge pull request #134 from LedgerHQ/load_app_callable_main

Making the main fucntion of loadApp.py callable

Merge pull request #133 from LedgerHQ/fix/dependencies

[fix] Align protobuf dependency versions with Ledgerwallet

Merge pull request #131 from LedgerHQ/pbo-delete-unused-constants

Delete unused constants/import