Delete old plugin signatures
Merge pull request #478 from sschaef/t-delete-old-signatures

Delete old plugin signatures
Removes reference to non-existing command

Fixes #1001807
Merge pull request #480 from skyluc/issue/no-command-for-restart-pc-1001807

Removes reference to non-existing command
Sync 'isDefined' in presentation compiler cache.

This fixes one race condition when hyperlinking between
projects. Project 'client' depends on project 'base'.
The sequence of events was:

- dependent project 'base' starts building
- the indexer for `client` kicks in and starts the PC. The PC is not
  yet initialized. PC starts without `base` classfiles on its class path
- `base` finished building and triggers a reset of the PC for `client`,
  that normally restarts with `base` classfiles on the class path
- reset is ignored (PC is still starting, and `isDefined` returns false)
- hyperlinking fails, because the target is not available on the class path
Resolve exception when using type mismatch quick fix

This is a regression due to refactorings in 8f42b9de31c9365d6f9c.

The regex that was used to check an internal message was updated to
work with Scalas new string interpolation feature. Unfortunately,
while the regex was the same the semantics changed because it was
tried to insert and extract a value into and from the string
interpolator at the same time, which is in this situation not possible.

Fixes #1001809
Merge pull request #483 from dragos/fix/race-condition-cached

Sync 'isDefined' in presentation compiler cache.
Updated sbt.version to 0.13.0-RC4
Merge pull request #484 from dotta/transient/update-sbt-to-rc4

Updated sbt.version to 0.13.0-RC4
Merge pull request #479 from sschaef/t-fix-type-mismatch-quickfix

Resolve exception when using type mismatch quick fix
Updated sbt.version to 0.13.0-RC5
Merge pull request #492 from dotta/transient/bump-sbt-version-number-to-RC5

Updated sbt.version to 0.13.0-RC5