Some code refactoring.
Preparation for Gpio interrupts.
Finalising "button" application.
Minor updates to README files.
Added uart1 logging application.
Fixing embxx external submodule reference.
Updating README file with new app description.
Added new 05_uart1_comms application.
This application uses "comms" module of the embxx library to
exhange messages via serial interface.
Fixing bugs in app 05_uart1_comms.
Using master branch (instead of develop) of embxx library.
Preparation for the release.
Release v0.2