Remove BASE64 reference testing as it's only libb64 now.
Improve the test to ignore \r and \n when comparing BASE-encoded
strings to not fail on system (unpatched) libb64.
Some crypto libraries (like CyaSSL, MatrixSSL and CommonCrypto) either
don't have or expose this functionality at all, expose only part of it,
or (like OpenSSL) have heavyweight API for it. Also, for the task as
easy as BASE64 encoding and decoding it's much better to use small and
simple specialized library.