misc changes (see PR)

[philippe44]

• use gettime_ms() which already exist (and time_t is an epoch so it's not really suitable)
• remove CONFIG_SQUEEZEAMP which is target specific
• eliminate warnings when they are in our code
• the PARSE_PARAM_XXX using function instead of macros is a total gain of less than 500 bytes. As the code does not work due to pointer usage, I've removed it. I tried to use _Generic() as we are C11, but it does not gain anything