* wifi_set_sleep_type returns a bool success flag.
* wifi_get_sleep_type seemed useless, just returning an argument. Added an implementation using sdk_pm_get_sleep_type.
* This fixes the problem of axTLS symbols hmac_md5/hmac_sha1 having same
name as symbols in libwpa (which have incompatible signatures)
* Also allows for easier identification and piece-by-piece removal of
binary functions.
* Some libc symbols are not renamed, list is in lib/symbols_norename.txt
