initial grunts file to run regression tests

originally done in a shell script
discard stdout for pdfgen because it causes grunt to fall over
remove genhtml dependency
add option to generate CSS coverage info
add compile task that generates CSS for all books
simplify task names
addition of Appendix CSS for headers/subheaders and associated fixes
Tables now render numbering in the answer key
Changed the image resolution to 150dpi
addition of styling for precalc eoc main header + merge of 150dpi setting code
add ccap-precalculus hook file for naginata
Various precalculus bugfixes dated 2/11/14 in the precalc review spreadsheet
Merged Staceys upstream changes (Glossary)
add error checking to make sure prereq files exist
better error handling when prereq file is missing
add color when skipping and add task descriptions
show the number of differences found for each book
update TODO and example config file
add prereq checking
make the prepare and diff tasks support a single book