fix(plug-in): correctly recover removed files
fix(plug-in): correctly recover removed files

This commit fixes the attempted recovery from removed files.
A few issues fixed in this commit:

* ALWAYS report browserify bundle errors
* only remove files that have actually been in the bundle
* Only attempt rebuild if a file was removed from the bundle

Closes #21

pmowrer/karma-browserify,Nikku/karma-browserify,sdtsui/karma-browserify