Add SBT version to example path for credentials file

As of sbt 0.13, the credentials won't be found if they aren't within a version directory.
Docs: use programmatic version in global base directory
Flush ObjectOutputStreams after construction

This protects against deadlocks between the writing and reading end,
since the ObjectOutputStream constructor writes a header, but does not
flush, and the ObjectInputStream constructor reads the header, and
blocks until it's read.
avoid deadlock in ConsoleOut.systemOutOverwrite

System.out can be reset after being captured by `val lockObject`.
Then locking `lockObject` and calling `println()` could lead to a
deadlock.
Fix implementation of Relation.size.

Nothing was actually using it yet, fortunately.
Allow zinc to use InternedAnalysisFormats.
sbt-vaadin-plugin added to community plugins
Log socket accept errors when forking tests

If an exception is thrown when accepting a connection from a forked test
agent, currently I'm seeing that all that happens is SBT hangs with no
output.  Thread dumps show that the main process is waiting for the
agent to return, while the agent is waiting for the server to send it
something.

This change logs the exception, so that at least the error can be
googled.  It also cleans up the server socket.
update to ScalaCheck 1.11.0
Explicitly, optimistically close export streams early: workaround for #937

This is a temporary workaround: it assumes nothing else uses these streams later.
This condition is ok for 'export' and test streams, since these are unlikely to
reuse these streams.  However, the proper fix is for the TaskStreams methods
to be smarter- they could open in append mode if the stream was closed.  The
streams associated with a task could be optimistically closed after it finishes executing.
(Any task can write to another task's streams, which is why it is an optimization only.)
Continuation of previous commit's workaround for #937: close test streams early
Add pending test case for #958 (incremental compiler bug)

The ticket contains detailed description of the problem. The test case
just shows that if we set `incOptions := sbt.inc.IncOptions.Default`
then the incremental compiler doesn't recover from compiler errors
properly.
Docs: fix typo.  Fixes #951.
Merge remote-tracking branch 'gkossakowski/error-in-invalidated' into 0.13
Add in the ability to launch non xsbti.AppMain classes.

* Deprecate old mainClass method on appProvider
* Create entryPoint method which represnets class used to launch instead.
* Create PlainApplication to wrap static `main` methods.  Can return
  either Int, Exit or Unit.
* Detect supported 'plain' classes via reflection.
* Add new unit tests appropriate to the feature.
Allow specifying sbt.boot.properties as a URI

This allows straight forward system independent generation of the
property, since URIs are well specified and only support one file
separator.
Recover from class files and Analysis object getting out of sync.

The #958 describes a scenario where partially successful results are
produced in form of class files written to disk. However, if compilation
fails down the road we do not record any new compilation results (products)
in Analysis object. This leads to Analysis object and disk contents to get
out of sync.

One way to solve this problem is to use transactional ClassfileManager that
commits changes to class files on disk only when entire incremental
compilation session is successful. Otherwise, new class files are rolled
back to previous state.

The other way to solve this problem is to record time stamps of class files
in Analysis object. This way, incremental compiler can detect that class
files and Analysis object got out of sync and recover from that by
recompiling corresponding sources.

This commit uses latter solution which enables simpler (non-transactional)
ClassfileManager to handle scenario from #958.

Fixes #958
simplified settings core example (as per `util/collection` `SettingsExample`)
Generate an error when the incremental compiler is given relative source files.  Fixes #923.

Review by @gkossakowski
Fix type error in example code

Fix #971.

Note that this is no complete fix, because this solution uses an
operator which is not any more described in the guide for 0.13.