Package-level Javadoc

Provides support for the runtime platform, core utility methods and the extension registry.

## Package Specification

This package contains three components:

- APIs related to the runtime platform itself (provided by the `org.eclipse.core.runtime` plug-in)
- Various utility types such as `Path`, `IPath` and various flavours of progress monitors (provided by the `org.eclipse.equinox.common` plug-in)
- Extension registry mechanism (provided by the `org.eclipse.equinox.registry` plug-in)