Cover page functionality

This release is backward compatible with prior releases.

What's new in this release:

• added the frontcover option to the package.
• added a bunch of booleans to make things cleaner in the code.

To generate a front cover:

• Add \usepackage[...frontcover=true...]{corporate} when calling the package.
• Define the authors' names and affiliations in the preamble:
  • \coverauthor[1]{Myname},
  • coveraffiliation[1]{MyAffiliation}
• Add \makecover before \maketitle to generate the cover page.