First code for ImageWatermark task. Still needs some tests and tweaks
rect property on ImageWatermark task is now optional
Added documentation for ImageWatermark Task
Merge branch 'master' into feature/ImageWatermarkTask

Conflicts:
	BumpVersion/BumpVersion.Tests/BumpVersion.Tests.csproj
	BumpVersion/BumpVersion/BumpVersion.csproj
	README.md
Merge pull request #4 from TheSylence/feature/ImageWatermarkTask

ImageWatermark task