Add failing test for issue #6 Cross-project dependency
Change the strategy how to handle output files

By facing issue #6, we should have managed files referenced by compile
targets, because they are also compiled implicitly.

This commit changes how we handle output files.

We give --outDir option to tsc with a temporary directory path so that
all files generated by tsc command go to the directory, and we can
manage them properly. No more "mark and sweep" is needed.

However, this has a side-effect that causes sourcemap files to have
unsolvable relative path to the source files.

So we add sourceRoot option and outDir option to manage with this
problem. sourceRoot option makes paths in sourcemap files absolute,
and outDir option is a hint for Compiler where the output files are
going to, so that it can correct paths in sourcemap.
Add a notice about sourcemap relative path to README
Add test case for in-place compile
Fix file.path of output files to reflect outDir option
Remove js file unexpectedly commited
More complicated test for cross project
Fix paths in sourcemap file for Windows
Fix compiler spec sometimes fails by async timing problem
Merge pull request #7 from kotas/issues/6

Change the strategy for handling output files