Wrapping mkvmuxer and mkvparser in the libwebm namespace is no
longer necessary now that the tree reorganization is complete.
Put mkvmuxer and mkvparser namespaces back in the global
namespace to avoid unnecessary churn in downstream code.
Change-Id: I13a4fe0143d20bb2bb6038078c68636ff2af0c29
- Use .cc and .h everywhere.
- Update includes/include guards.
- Remove extra makefile targets necessitated by previous mix
of cpp/cc.
Change-Id: I7aad29152d4177937f8f42927c16c6572228c104