* Rework WiFiClient
Rework WiFiClient to correct error where making a copy of a WiFiClient object resulted in the socket being closed prematurely.
Added loop and select to write to handle/prevent EAGAIN errors.
* Rework WiFiClient to use shared_ptr
Rework changes to utilize shared_ptr rather than manually maintaining reference count.
Revert changes to write
* Incorporate comments from review
Move WiFiClientSocketHandle and fd() into WiFiClient.cpp
The send call may return EAGAIN. This indicates a recoverable error and a retry should be attempted. The current implementation treats this as a fatal error. Further, the current implementation strips the error code, setting it to 0, which prevents the caller from handling it directly.
This change utilizes select to verify the socket is available prior to calling send and will retry on an EAGAIN condition.
WiFi and BlueTooth can now be started and stopped at will.
basic functions added to esp32-hal to start and stop the BT radio
SimpleBLE class added to show the most basic functionality
Example to show how to switch between BT, WiFi or Both
Currently there is bug in WiFiUDP library when you want to use beginPacket(...) without listening on socket (without calling begin(...) first). You can't send any data because socket is not open and also tx_buffer is not allocated which cause crash while writing data to tx_buffer.
currently ```esp_wifi_init``` have to be called in ```app_main``` or
WiFi will fail to boot. When possible to boot later, code will be moved
into ```_esp_wifi_start``` to be executed when necessary
IDF Options:
- Autostart Arduino (implements app_main)
- Disable HAL locks
- Set HAL debug level
- Auto-connect STA if configured (else will connect after WiFi.begin())
