* Refactor the PEM saving code in `test.c`, so its not using large 4K buffer and calculates based on DER.
* Enable ECC key generation test even without `WOLFSSL_KEY_GEN`.
* Added `ECC_KEYGEN_SIZE` macro for ECC key generation testing.
* Refactor ECC DER key generation to use `ECC_BUFSIZE`.
- increase FP_MAX_BITS for OpenSSH
- Add helpful loggin API (names are self-explanatory)
-- wolfSSL_GetLoggingCb
-- WOLFSSL_IS_DEBUG_ON
- Define WOLFSSL_EC_METHOD as an alias of WOLFSSL_EC_GROUP
- Add wolfSSL_EC_GROUP_method_of which really just returns the group itself
- Add wolfSSL_EC_METHOD_get_field_type which gets the curve type of the WOLFSSL_EC_GROUP(remember that WOLFSSL_EC_METHOD is an alias of WOLFSSL_EC_GROUP for now)
- Modify Base64_Decode so that it accepts arbitrary PEM line length
- Modify PemToDer so that it accepts private keys with a custom -----BEGIN * PRIVATE KEY----- header
* Add define `WOLFSSL_BASE16` to explicitly expose base16 support.
* Add `./configure --enable-base16` option (disabled by default in configure, but enabled in coding.h when required internally).
* Added base16 tests in test.c `base16_test`.
* Enabled base64 decode tests when `WOLFSSL_BASE64_ENCODE` is not defined.
