v1.4.0-beta.1

This version of statcheck has several changes under the hood compared to version 1.3.0 on CRAN. It currently retains a more modular approach, with more separate functions that have a specific task and regular expressions that are built up from smaller building blocks. Furthermore, the column names of the final statcheck output have changed as well.

Version 1.4.0-beta.1 currently passes all unit tests, but still contains a few hacky and potentially buggy fixes (hence the beta pre-release).