feat(plug-in): insert bundle before preprocessed files

This commit tries to figure out the correct position of the bundle file
based on config.files and config.preprocessors.

By doing so, it makes sure that external (non-commonJS) files can be
inserted before the bundle file and get correctly discovered.

It compares defined files against browserified files defined in
config.preprocessors and inserts the bundle in the first matching file
found. If none is found, it defaults to the old behavior. That is, it
inserts the bundle in the file list at position zero.

Closes #1
chore(package.json): add tag + update description
chore(project): release v0.3.0
chore(example): bump karma-bro version
docs(README): add non-cjs library loading example
feat(plug-in): support options for browserify transforms
test(plug-in): add test for configuring transforms

Adds tests for #2
chore(project): release v0.4.0
chore(plug-in): wtf did the test not break?
fix(plug-in): correctly check whether source-map exists

This commit ensures we do not throw an exception when a bundle contains no
files (and this the source-map is null)
test(plug-in): test source-map support
chore(project): update watchify dev dependency
feat(plug-in): add browserify plugin option
chore(project): release v0.5.0
feat(plug-in): add prebundle support

This commit adds the ability to configure the bundle prior to
minification.
docs(README): refactor usage section
chore(project): release v0.6.0