* pull in debug module, to make debug messages optional ([#36](https://github.com/istanbuljs/istanbuljs/issues/36)) ([189519d](https://github.com/istanbuljs/istanbul-lib-source-maps/commit/189519d))
* read and apply any input source maps stored with coverage data ([#4](https://github.com/istanbuljs/istanbul-lib-source-maps/issues/4)) ([aea405b](https://github.com/istanbuljs/istanbul-lib-source-maps/commit/aea405b))
* discard more bad source map positions ([#3](https://github.com/istanbuljs/istanbul-lib-source-maps/issues/3)) ([ed7b27f](https://github.com/istanbuljs/istanbul-lib-source-maps/commit/ed7b27f))