Fix file position after WriteHeapDump, read header of heapdump in scanner.
Fix wrong size for read.
First step of migration. See TODO's in decoder.go
Update ReadField and Field to use correct size.
Rewrite writer/encoder and add Decodable interface.
Fix Decodable test.
Add Encodable interface.
Simplify encoder.
Change size of reads in decoder.
Rename ErrCanAddrFalse to ErrCanSetFalse and check only in one function in decoder.
Remove unnecessary test messages.
Add test for output size of writer. Fix wrong size for boolean.
Refactor code, fix reading and writing of values.

Fixes reading, writing, encoding and decoding of values.
Also renames a few variables, removes unnecessary error messages, adds more tests and cleans up the code.