Commit partial changes.
Added unit test cases for create/delete/list shares/files/directories.
Merge branch 'dev'
BUG: 1760998 - [PowerShell for XSMB] Cannot access file service when -Environment is specified for new-azurestoragecontext

Fixed a merging issue where file endpoint is set null when specifying -Environment.
Merge branch 'dev'
Merge branch 'upstream/dev'
Merge branch 'dev'
Refactored DM wrapper to allow mock up.
Added unit test cases for upload/download files.
Merge branch 'upstream/dev'
Resolved merge issues of AzureStorageContext moving.
Merge remote-tracking branch 'ogail/storage' into dev
Added unit test cases for WindowsAzureEnvironment as requested.
add the help content for file commands
Merge branch 'dev' of https://github.com/flyrobin/azure-sdk-tools.git
Added support for tags on resource level (1561924)
Added support for tags on resource group level (1561924)
Get resources by tag (1561927)
Merge branch 'dev' of https://github.com/WindowsAzure/azure-sdk-tools into tags

Conflicts:
	src/Common/Commands.ScenarioTest/Common/WindowsAzurePowerShellTokenTest.cs
	src/Common/Commands.ScenarioTest/Resources/ResourceManager/ResourceGroupTests.ps1
	src/Common/Commands.ScenarioTest/Resources/SessionRecords/ResourceGroupTests/TestCreatesNewSimpleResourceGroup.json
	src/Common/Commands.ScenarioTest/Resources/SessionRecords/ResourceTests/TestCreatesNewSimpleResource.json
Worked around DM lib bug 1887176 which would hangs the cmdlet when providing uri for the source blob and the dest blob exists with a different blob type during copy blob operations.