Migrate PackratParsers tests to JUnit.

Most of the migration is straightforward. One exception is packrat3
(migrated to `test3` method). I simplified returned result by getting
rid of useless Unit by changing this rule:

  repMany1(a,b) ~ not(b)

into this rule:

  repMany1(a,b) <~ not(b)

Also, I made all rules to be type safe.

When constructing expected results, I decided to use scala.Symbol that
allows us to use a bit more concise syntax for construction of one
character strings. See `threeLists` method for details.
Migrate RegexParsers tests to JUnit.
Migrate JavaTokenParsers tests to JUnit.

The unicode strings has been escaped using

  native2ascii -encoding utf8 a.txt b.txt

command.
Reduce code duplication in PackratParsersTest

Extract common code that parses strings and extracts results
into helper methods.

In test1 and test2 I named the helper method `check` because it checks
if expression-evaluating parser calculates the correct result.

In test3, we are interested in parsing result (Success or Failure) thus
helper methods are named `assertSuccess` and `assertFailure`.
Merge pull request #7 from gkossakowski/junit-migration

JUnit migration