Port the Analysis lookup change

[eed3si9n]

(This PR is implemented on top of #176 (Revert #165 but keep some of the changes). The relevant commit(s) are 8dd3aca onward.)

All it does is add the following methods on PerClasspathEntryLookup:

    /** Provides the Analysis for the given classFile. */
    Maybe<CompileAnalysis> lookupAnalysis(File classFile);

    /** Provides the Analysis for the given binary class name in an external JAR. */
    Maybe<CompileAnalysis> lookupAnalysis(File binaryDependency, String binaryClassName);

    /** Provides the Analysis for the given binary class name. */
    Maybe<CompileAnalysis> lookupAnalysis(String binaryClassName);

This enables a more efficient implementation of Analysis lookup that doesn't involve classpath lookups.

Ref gkossakowski/zinc@8092cd8
Ref gkossakowski/zinc@bd0dde3
Ref gkossakowski/sbt@c45f580
Ref sbt/sbt#2525

/review @gkossakowski, @dwijnand

[romanowski]

Genernally we can't skip classpath checks and focus purly on analysis since then we are failing to capture changes in classpath (e.g. shadowing of classes). Please test your implementation with tests from #175 since failures there was reason why I abandon my previous implementation (from #165 ).

[eed3si9n]

Closing this in favor of #180