Addresses issue #1022.
Blanket wide to all .c and .h files. Some files originating from ST are difficult to deal with (license wise) so it was left out of those. Also merged modpyb.h, modos.h, modstm.h and modtime.h in stmhal/.
MICROPY_ENABLE_FLOAT is automatically set in mpconfig.h if MICROPY_FLOAT_IMPL is set to a non-zero value.