Add inheritance tests

Authored by @somedave, cherry-picked from
276e0d0f855ac2a3097af7ebc9614e0c91412f3a and
ec3cc12d1f7b60cd1292725e2f3bc98aa0ce6a9b
Add .gitattributes to normalize line endings
Normalize line endings
Merge @somedave's fix for bug #61
Cleans up the Extends and Block render state caching design.
Fixes a bug with the new per-render block state tracking
Decrease maximum scope stack count

because Resharper's test runner now throws StackOverflowException if max
scope count > 95
Add VS2012 .sln
Remove website projects from DotLiquid-2010.sln
Remove changelog from 2008 and 2010 solutions
Add VS2010-specific project files
Upgrade VS2012 projects to .NET 4.5
Decrease maximum scope stack count further

so that it works correctly on VS2008 / .NET 3.5
Moved changelog to repo root
Update changelog
Implement Guid as a supported primitive type.

Implements #68.
Clarification-test for #69.
Add another test related to #69.
Tablerow tag no longer throws exception when

specifying limit or offset attributes. Fixes #66.
Added ability to choose what gets rendered for a safe type when used as the RHS result versus a part in a variable chain.

Extended DropProxy with a new interface that allows for
{{registeredType}} and {{registeredType.RegisteredProperty}} to both be
supported.  Also added a method to override default value type (and
other registered types for that matter) rendering -- useful in
localization, globalization, and customization.