Auto-generate file name of the resume based on user name

Minutes of coding saving seconds of copying.
Added the ability for the resugen to merge multiple YAML files

The goal of this is to enable inclusion of private information in the
resume while keeping it out of source control.  The new syntax is:

   python -m resgun.main resume.yaml template.jinja2 output_path \
       --extra file1.yaml file2.yaml
Fill in the location information in the latex template

It's important information for prospective employers, and this
implementation is optional.
Add the ability to include a private "personal.yaml" file in the build

This file is merged into the main resume.yaml file and allows for inclusion
of things like a phone number and street address without checking them in.
Cleanup a few extra hard to read line using the "%" break lines

Took a little while to find the that character but increases the
readability a little.  Not too much I can do about the latex using "{" and
jinja2 using "{" for it's special template character.
Move location information to non-checked in personal.yaml file

It now includes my full address, and we don't want that on the internet.