Remove sha1 and base64 functions

[robiwano]

Having sha1 requires dependency on OpenSSL when it is not necessary. A filesystem library should ONLY provide the basic functionality to traverse folders, and provide means to read/write to file streams. Nothing more.

Hash/base64 etc. can, and should, be provided outside the library.

[chrisjd20]

I personally like the base64 functionality. Just my two-cents.