Configurable test case name

Hello!

This pull request concerns the following issue: https://github.com/Pragmatists/JUnitParams/issues/2

I've created a new annotation that can be used for test case name configuration. Just like in JUnit, but you know JUnit parameterised tests suck. =)
Here is an example of usage:
``` java
  @Test
  @Parameters({ "1,1", "2,2", "3,6" })
  @TestCaseName("factorial({0}) = {1}")
  public void custom_names_for_test_case(int argument, int result) { }
```
It will produce tests with names:
factorial(1) = 1
factorial(2) = 2
etc...

I tried to introduce the smallest changes to the core. Can you review it? I'm ready to make any modifications you want. Seriously, me and my colleagues use your excellent lib quite often and the only thing we miss is a configurable test case name generation.