Add git, cmake and build-essential to Ubuntu cheatsheet

These three extra packages complete the list of build dependencies for
Ubuntu/Debian.
Update .gitignore and remove three auto-generated files from git

This ignores files generated by cmake and make, and drops three
files from git that are auto-generated by cmake.
It also un-ignores files that no longer exist, as executables are
now generated in bin/, not in the src/ directory.
With these changes, "git status" and "git diff" now worki properly.
Fix compiler warnings caused by trailing commas in enum definitions
Remove compiler warnings from log_*("MESSAGE")

calls to the log_error and log_info macros with a single constant argument
make GCC complain about non-ISO compliance. Reduce the noise by providing a
dummy argument.
Remove unused variables in IMPLEMENT_SERIALIZE