CanLoadSimpleProject: Fix existential type warning
Use .sbt/jvmargs .sbt/jvmprops (no dot on file inside dotdir)
Remove protocol type aliases from sbt.client

 * in some cases (specifying a type parameter for example) these
   don't seem to be interchangeable with the original type
 * having two paths to the same type name is confusing for
   API users
 * we only had a haphazard subset of sbt.protocol aliased into
   sbt.client anyway
 * DRY
Merge pull request #203 from sbt/wip/havocp-remove-client-aliases

Remove protocol type aliases from sbt.client
Remove Format for java.net.URL

Using URL in a data type is a terrible idea because
the hashCode and equals do DNS lookups.
Plus this was unused.
Merge pull request #204 from sbt/wip/havocp-remove-url-format

Remove Format for java.net.URL
Do not define Format instances

The way play-json is intended to be used, best I can tell, is
that you define only Reads and Writes, and let Format get created
implicitly from those. If you define a Format then any attempt
to have a Reads becomes ambiguous.

We were also not using some of the generic Reads and Writes
instances that we could have used, so got rid of some
duplicated serializers we don't need anymore.

Also changed to define only Map[File, T] serializer, rather than
generic Map[A,B], and the same for Relation. This allows us
to use a plain JSON dictionary and the Map[String,T] serializer
already provided by Play.

Split out some of the serializers to a private GenericSerializers
object, which both makes them private, and also fixes some
initialization order problems.
Merge pull request #205 from sbt/wip/havocp-format-cleanup

Do not define Format instances
Merge pull request #202 from sbt/wip/havocp-jvmargs

Use .sbt/jvmargs .sbt/jvmprops (no dot on file inside dotdir)
Merge pull request #200 from sbt/wip/havocp-fix-warning

CanLoadSimpleProject: Fix existential type warning
Add serialization for Ivy ModuleId