Input parameter null checking for AstFactory methods
Merge pull request #3240 from Randy-Ma/master

Add missing files and adjust the path for two test cases
Never return null for AstIdentifierBase unless has error
Delete SystemTestBase.cs

This file has been renamed as RevitSystemTestBase.cs
Merge pull request #3243 from ke-yu/fix_magn5096

Fix magn5096: AstFactory methods require null checks
sync the project structure as expected at DynamoRevit
Merge pull request #3247 from Conceptual-Design/DynamoRevit2014

sync the project structure as expected at DynamoRevit
sync project as well as test setups with DynamoRevit
Merge pull request #3249 from Conceptual-Design/DynamoRevit2014

sync project as well as test setups with DynamoRevit
merge with master
Move test/System/revit/Samples/ to test/System/Samples/Samples/
Solution files for DynamoRevit and Install renamed
Merge pull request #3251 from Conceptual-Design/DynamoRevit2014

Merge master  to DynamoRevit2014 branch
Merge branch 'DynamoRevit2014' of https://github.com/DynamoDS/Dynamo into DynamoRevit2015

Conflicts:
	src/Dynamo.All.2013.sln
Merge pull request #3252 from Conceptual-Design/DynamoRevit2015

merge DynamoRevit2014 to DynamoRevit2015