Working version of DependencyAnalysis

* passes all tests, including BOSH release
* does not detect cycles in dependencies
Signed-off-by: Phan Le <ple@pivotallabs.com>

Signed-off-by: Phan Le <ple@pivotallabs.com>
Starting using DependencyAnalysis in Compiler

Signed-off-by: Phan Le <ple@pivotallabs.com>
Move validation and compile logic into their own package.

Signed-off-by: Phan Le <ple@pivotallabs.com>
Refactor Validator to ReleaseValidator

Signed-off-by: Phan Le <ple@pivotallabs.com>