Implement Base32 decoding for new EncoderDecoder

[05nelsonm]

Part 2 of #41

This PR:

• Implements the decoding for all 3 spec's (Crockford, RFC 4648 section 6, RFC 4648 section 7) using the new EncoderDecoder
• Maps the old decoding extension function bodies to use the new EncoderDecoder for Base32.
• Creates a new class for commonizing bit buffers (so it can be reusable in higher level modules, such as Base32).
• Fixed a bug in Decoder extension functions where padding was being sent unnecessarily.

[05nelsonm]

I think in 2 or so refactors and adding tests, this will be pretty solid implementation. After adding the BitBuffer abstraction, it is really simple to create encoders.

I think though there can be more things shifted to encoding-core, like skipping over new lines/spaces, or handling padding. Those 2 things are expressed in the base configuration and should be used to mitigate duplicate, unnecessary code.

[05nelsonm]

I think though there can be more things shifted to encoding-core, like skipping over new lines/spaces, or handling padding. Those 2 things are expressed in the base configuration and should be used to mitigate duplicate, unnecessary code.

Resolved in commit 52f426b 💪