TypeScript 2.0.0-beta bug affects some build configurations

[cartant]

@basarat For your reference, I've traced my TypeScript 2.0.0-beta problems to a TypeScript commit that changes the handling of source files and common and output directories. I've submitted an issue.

[cartant]

It seems that this is a tsify problem - not a TypeScript problem - as getCanonicalFileName is implemented in the host.

The TypeScript implementation of getCanonicalFileName simply converts the path to lower case, whereas the tsify version returns a relative path - which breaks the TypeScript 2.0 implementation of getSourceFilePathInNewDir.

[cartant]

This should be fixed in #171.