Implement DeclareFieldsTransformer

[jonesdevelopment]

Declares fields that have constant values:

private static final int a = 1;
private static final int b = 2;
private static final int c = 3;

turns into

private static final int a;
private static final int b;
private static final int c;

static {
  a = 1;
  b = 2;
  c = 3;
}

This makes it possible to harden the obfuscation of constants (by allowing other transformers to access these values since they'd normally only be accessible through field.value).