Add ps for generating semver version numbers

ImageSharp.sln

@@ -12,6 +12,7 @@ EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "SolutionItems", "SolutionItems", "{C317F1B1-D75E-4C6D-83EB-80367343E0D7}"
 	ProjectSection(SolutionItems) = preProject
 		build\appveyor-project-version-patch.js = build\appveyor-project-version-patch.js
+		build\appveyor-semver.ps1 = build\appveyor-semver.ps1
 		appveyor.yml = appveyor.yml
 		build\dotnet-latest.ps1 = build\dotnet-latest.ps1
 		global.json = global.json

appveyor.yml

@@ -3,7 +3,11 @@ os: Visual Studio 2015
 
 init:
   - ps: iex ((new-object net.webclient).DownloadString('https://gist.githubusercontent.com/PureKrome/0f79e25693d574807939/raw/8cf3160c9516ef1f4effc825c0a44acc918a0b5a/appveyor-build-info.ps'))
-  
+
+environment:
+  # Version Suffix
+  version_suffix: alpha
+
 install:
 # Use the install script to grab the latest dotnet install
 - ps: iex .\dotnet-latest.ps1
@@ -13,11 +17,14 @@ install:
 # the parent CMD process).
 - "SET PATH=C:\\Program Files\\dotnet\\bin;%PATH%"
 
+- ps: .\build\appveyor-semver.ps1
+
 assembly_info:
   patch: true
   file: '**\AssemblyInfo.*'
-  assembly_version: '1.0.0.{build}'
-  assembly_file_version: '1.0.0.{build}'
+  assembly_version: '$(appveyor_build_version)'
+  assembly_file_version: '$(appveyor_build_version)'
+  assembly_informational_version: '$(mssemver)'
 
 before_build:
 - cmd: >-

build/appveyor-semver.ps1

@@ -0,0 +1,16 @@
+$version=[Version]$Env:APPVEYOR_BUILD_VERSION
+$version_suffix=$Env:version_suffix
+
+$basever=$version.Major.ToString() + "." + $version.Minor.ToString() + "." + $version.Build.ToString()
+
+$semver = $basever + "-" + $version_suffix + "." + $version.Revision.ToString().PadLeft(6,"0")
+$mssemver = $basever + "-" + $version_suffix + "-" + $version.Revision.ToString().PadLeft(6,"0")
+$appveyor_version = $mssemver
+
+$Env:semver = $semver
+$Env:mssemver = $mssemver
+$Env:appveyor_version = $appveyor_version
+
+"Envrionment variable 'semver' set:" + $Env:semver
+"Envrionment variable 'mssemver' set:" + $Env:mssemver
+"Envrionment variable 'appveyor_version' set:" + $Env:appveyor_version