Reduce deliverable size by keeping Guava only as a test dependency

[paplorinc]

Most probably use this library in their tests, where additional dependencies probably don't matter that much.
I want to use it for production, where transitive dependencies should be minimized.
One of the bigger dependencies of the lib is Guava (~3 MB) and most of the production uses (~70, we could leave it for tests) could easily be replaced with more focused dependencies (some may be more difficult to eliminate, see below).

The use categories seem to be:

• checkNotNull, checkArgument, firstNonNull - we can copy the trivial implementations to our own helpers
• MoreObjects.toStringHelper- we can easily generate the same from IDEA
• Objects.hashCode, Optional<CyclicReference>, Joiner.on(" -> ") - can be replaced with Objects.hash and the rest of the JDK 8 alternatives
• ImmutableSetMultimap<String, CopyMethod> - not sure yet, would unmodifiableMap of LinkedHashMap suffice here - as used in other places? Or maybe VAVr could be used to provide persistent datastructures
• ImmutableList<AnalysisResult>, ImmutableSet.copyOf, ImmutableList.of(1) - seems a bit inconsistent, when are we using immutable ones and when are we just wrapping with unmodifiable?
• CacheBuilder.newBuilder().recordStats().build() - is this any different from ConcurrentHashMap in our case?
• transform(dottedClassNames, AllowedIfOtherClassIsImmutable::new) - seems like a simple stream.

If you think this is a good idea, I can provide some PRs for the categories.