basePath & regExp now can be configured

[StyleT]

Now user can specify base path or regular expression

[StyleT]

Anyone is here?

[bustardcelly]

@StyleT

I appreciate your interest and this PR.

I am currently deciding on the relevance of its improvement for the following reasons:

1. Would not overriding a basePath to a file essentially mean that you can possibly point it to any file, therefore giving it false-y file hash?
2. Providing a custom regex would A) cause more developers (and opened issues) having problems with their own faulty regex thinking it is gulp-rev-append issue and B) be better suited for a tool such as gulp-replace

Truthfully, it's Number 2 that really is keeping me from accepting this PR (along with no additional test to ensure that the changes do what they propose). I use gulp-replace quite often and I think it would be a better tool in what this PR may be trying to accomplish.

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I do appreciate your work and would like to hear your thoughts to make me change my mind.

I also apologize for the late response; life happens :)

[pasqLisena]

+1 for the PR! I need it because I am moving the html from the src to the dist folder, and in src there are not the compiled files to which the html refers (I am using typescript and stylus).