Unified 'get' and 'put' from .Internal modules.
Unified 'prompt' function from .Internal modules.
Unified 'demanInput' and 'wantInput' for ByteString and Text.
Unified 'ensure' for ByteString and Text.
Unified 'satisfy' for ByteString and Text.
Unified 'endOfInput' and 'atEnd' for ByteString and Text.
Added Chunk.chunkElemToChar, needed to implement CharParsing.satisfy in ekmett/parsers.