Fix strftime tests, which was broken for %W
Move file system to Template Configuration
Use template configuration for registering tags
Move safe type transformers to template configuration
Move value type transformers to template configuration
Move filters to template configuration
Use new template configuration in tests
Forward template configuration to included template
Forward template configuration to extended template
Allows block tag to know if it has been overridden
Changes level of accessibility of a tag variables
Merge remote-tracking branch 'upstream/master'
Merge remote-tracking branch 'amoreira/refactor/tag-variables-access'

Conflicts:
	src/DotLiquid/Tags/Extends.cs
	src/DotLiquid/Tags/Include.cs