Fix #525: Closure emits spurious warnings for @JSExported properties.
Fix #518: Closure sometimes eliminates all our exports.
Merge pull request #527 from sjrd/fix-closure-warns-and-bug

Fix closure warns and bug
Report call stack when warning for non-existent class.
Merge pull request #529 from sjrd/improve-dce-warnings

Report call stack when warning for non-existent class.
Include the core info files directly in the tools.

This removes the need to chain them through our library + tools
API for no good reason, and hence eliminates a quirk from our
tools API.
Change the API and serialization format of class info.

In 0.4.x, class info were stored in .sjsinfo files with a JSON
format. In the initial transformations to serialize the IR, we
have limited the changes and still produced class info as an
IR tree with the exact same JSON structure as before.

However, this format of serialization is unnecessary complex and
slow to parse, which is a pity since class info (and even more
importantly the subset of "rough class info") should be parsed
quickly.

This commit introduces a binary format for serializing the class
info, and in the process lifts the class info as a proper API in
the IR package.
Add partest interface compile to travis
Merge pull request #530 from sjrd/info-format

Direct serialization format for class info
Fix shadowing rules in ClasspathBuilder for jars.

Files in jars coming earlier in a classpath should shadow files
with the same *relative* path to their jar coming later in a
classpath. This behavior was broken in
d97f7d090f44a8399df72e82f876e822a9fc27d7 and so here's the fix.
Fix #526: Remove .sjspack files, inline info into packfile
Fix #515: Implement isInfinite for java.lang.Float and Double
Add tests for +-Infinity.toString() - comes from #516.
Merge pull request #528 from gzm0/remove-packfiles

Fix #526: Remove .sjspack files, inline info into packfile
Merge pull request #537 from sjrd/fix-classpath-shadowing

Fix shadowing rules in ClasspathBuilder for jars.
Merge pull request #532 from sjrd/isinfinite

Fix #515: Implement isInfinite for java.lang.Float and Double
Serialize Positions in IR incrementally.

It means: as diffs wrt the last position serialized, with a compact
format. This divides almost by 2 the size of .sjsir files.
Merge pull request #533 from sjrd/serialize-pos-incrementally

Serialize Positions in IR incrementally.