Add HW.1

Proofread
Update default score
Update logo
Fix typo
Fix square logo size
Spelling
Dev Docs: Describe Almost All Remaining P2P Network Messages

* Describes all remaining messages except filterload. Specificially, the
  following messages are described: Addr, Alert, FilterAdd, FilterClear,
  GetAddr, Ping, Pong, Reject, VerAck, and Version

* New makefile test: report broken markdown tables

* Put relevant protocol version changes at the top of all message
  subsections.
New name
Update ja translations
Normalize references to protocol versions
Fix a few typos
Modify validation text for wallets requiring additional full node software (closes #645)
Merge remote-tracking branch 'saivann/protocolversions' into control-messages
Dev Docs: Prefix Table Rows With Added/Updated Status

Suggested by @saivann (thanks!)
Fix broken links
Merge remote-tracking branch 'remotes/btchip/hw1'
Set license files and headers for bitcoin.org's content
Avoid printing "language disabled" twice in sitemap.rb and template.rb
Delete unused file
Dev Docs: Link To CC-BY License For Covered Code

A code snippet from the wiki was correctly attributed to its author, but
I didn't realize I also had to link to the license.  Corrected.