Partial impl of LocalActorRefProvicerSpec (#59)

Still left to implement (and functionality?) for invalid actor names.

Changes:

- Changed behavior of ActorOf so it doesn't copy Props when no Dispatcher or
Mailbox is given in the Deploy object, or when there is no Deploy in
configuration.

- In Deploy, force Scope, Dispatcher and Mailbox to be set to NoScopeGiven,
NoDispatcherGiven and NoMailboxGiven in case of null values to
constructor.
LocalActorRefProviderSpec, test names

Changes to regex handling because of differences between CLR and JVM:
- a-zA-Z0-9 instead of \w (latter includes non-Latin characters)
- added CultureInvariant option
- added ^$ because regex to match whole string (Scala does this when
  matching regexes using pattern matching)

Changed exception type and messages for null/empty names.