* Added support for zero-length TLV
* Added SEPARATOR as a formal kTLVType (and updated listControllers() to use)
* Added `uint8_t *buf(tagType tag, uint8_t *src, int len);` to load buffer needing external memcpy (and updated listControllers() to use)
A 16-byte SALT with a leading zero would be sent as only a 15-byte number. The chance of this occuring is 1 in 256, which is small but still significant. Solution is to specify required size of MPI output in loadTLV. This forces mbedtls_mpi_write_binary() to pad with leading zeros.
Also eliminated unused code (TLV pack_old).
1) Used `const char *` instead of `char *` where appropriate, including the need to create a dummy blank string for us in certain places.
2) Set initialization of WiFiClient to 0 instead of NULL, since WiFiClient is not a pointer (probably don't need to set it to anything since WiFiClient overrides the boolean operator anyway).
3) Cleaned up some of the messaging and logic when WiFi tries to connect so that users know to wait a bit.
4) Only remaining warning messages are for casting SpanService to (void *), which I think i unavailable (and is not forbidden).
To Do: Go through examples and check for warnings (will likely need to convert `char *` to `const char *` in many places.
Convention is that every *.cpp references, in this order:
1) Any required core librries
2) Its own *.h (i.e. Foo.cpp -> Foo.h)
3) All other *.h files needed by the cpp, UNLESS those *.h files are already in its own *.h file. Must include all *.h files that are not in its own *.h file even if it is others that are referenced.
This change allows the user to set the log-level with homeSpan.setLogLevel() instead of needing to change in Settings.h. Next up: Update Example that introduces VERBOSE to instead use setLogLevel(). Consider adding an interactive 'L' command to change this during run-time.
Also, added "#pragma once" to every *.h file to prevent duplication of definitions. TO DO: Review all #include to ensure sanity across all files.
Gregg