Merge pull request #334 from tyrcho/master

fix issue 332
Merge pull request #335 from tyrcho/fixes

New fixes from tyrcho
Rename readme.md to README
Rename README to README.md
Create CONTRIBUTING.md

Inspired from https://github.com/tiimgreen/github-cheat-sheet#contributing-guidelines and https://github.com/puppetlabs/puppet/edit/master/CONTRIBUTING.md
Update CONTRIBUTING.md
Merge pull request #337 from tyrcho/master

Contributions guidelines
Release notes for v0.17.2
Update Version To 1.7.2

Need to re-upload the release.
Maven release versions updated to v0.17.2 by mvn release:prepare
Updated Version to 1.7.2

Need to re-upload the release.
Merge remote-tracking branch 'origin/master'
Fixed NullPointerException when loading certain cards from HearthStats.net
Updated version numbers to v0.17.3 (pre-tagging)
scala file
Updated version numbers to v0.17.3 (post-tagging)
fix for non collectible returned by API
Merge branch 'master' of
https://github.com/HearthStats/HearthStats.net-Uploader

Conflicts:
	uploader/src/main/scala/net/hearthstats/CardUtils.scala
fixes image download URLs (#345, #346)
Merge pull request #349 from tyrcho/fix-url

Fix url for images