Merge pull request #16 from abjerner/master

Various changes and improvements for the part involving Vimeo
Updated README.md to follow my earlier changes for Vimeo
Merge pull request #17 from abjerner/patch-4

Updated README.md to follow my earlier changes for Vimeo
Work in progress - ImageGen extension
Quick update/fix on unreachable code
Add in property alias for media ImageGen extension helper
Null checks for some string methods
Tweaks and test execution for ImageGen
Delete some temp files that are excluded by gitignore anyway
Merge pull request #18 from Jeavon/master

Tweaks to ImageGen and some null checks on 2 string methods
Switch extension method from Core.Models.Media to IPublishedContent
Merge remote-tracking branch 'upstream/master'
Use propertyAlias parameter so that it can be changed to something other than umbracoFile
Merge pull request #19 from Jeavon/master

Switch extension method from Core.Models.Media to IPublishedContent