[453119] Add support for registering/retrieving adapters via TypeTokens.

- Changed AdapterKey to use TypeToken as an alternative to Class key.
- Introduced methods to IAdaptable to register and retrieve adapters via TypeToken in addition to Class.
- Moved google.guava package from fx-feature to common-feature.
[NONE] Update target to consume e(fx)clipse from Mars releases site.
[442973] Ensure e(fx)clipse is consumed from Mars releases site.

Removed repository dependency on e(fx)clipse site, using only the Mars release site instead (where e(fx)clipse minimal runtime feature is now included as well).