hacked a way so that we can mark old methods on IElasticsearchClient as obsolete as well as the old name of the renamed RequestParameters
namespace should not change for obsolete bwc placeholder classes
moved up/down casts hacks to Obsolete.cs and cleaned IndicesExistsAlias.cs up
added NEST bwc placeholders for renamed IndicesExistsAlias* classes
added bwc for #852, #851, #841
needed to implement bwc for ExplainDescriptor not ExplainRequest, namespace should not be Nest.Obsolete but Nest
Merge branch 'develop' into fix/renamed-descriptors
fix #853 finished bwc changes for new API endpoints that renamed descriptors / requests
Merge branch 'fix/renamed-descriptors' into develop