Merge pull request #3 from larshesel/use-stable-elixir

Use a stable version of Elixir
Merge pull request #4 from larshesel/parser

Well done!
Update .gitignore

Ignore documentation and emacs save files.
Move struct definitions out of parser module
Make parse_block_header return an ok tuple
Add transaction parsing

We can now parse the genesis block.
Add get raw block data function and test
Add higher level functionality for parsing block data chunks
Match again magic number when parsing a block
Add functionality to parse the entire blockchain file
Create bitcoind escript exposing parser functionality
Update .gitignore