1. Use bt_app_gap_init function
2. Add Security Simple Pair doc
3. Update README
Update SPP demo
1. Add input module for bt_spp_initiator demo to show the security simple pair features
2. Update README of bt_spp_acceptor and bt_spp_initiator demo.
Format comment in esp_a2dp_api.h
Format comment in esp_avrc_api.h
Format comment in esp_spp_api.h
Fix bt_discovery build err
Update HFP API guide error
Remove BTA_AV_DEBUG
Remove Trailing Whitespace & End of Files