Update Command-Line-Reference.markdown

Add FileConflictAction parameter to the list
Update Versioning.markdown

Add Behavior change in how NuGet updates dependency packages
Update Versioning.markdown

Fix format
Update Versioning.markdown

Fix format
Update Versioning.markdown

Add new line
Update Versioning.markdown

Fix URL link
Update Command-Line-Reference.markdown

Add possible values
Update Package-Manager-Console-PowerShell-Reference.markdown

Add FileConflictAction to powershell reference
Update Package-Manager-Console-PowerShell-Reference.markdown

Add space
Update Versioning.markdown
Update Package-Manager-Console-PowerShell-Reference.markdown
Merge branch 'nuget-2.5-danliu' into nuget-2.5