Reworking top half of sheet

Significant changes to the layout and functionality to the top half of
the sheet including a rework for the core stats, hit dice, save throw
and skills system.  Macros in the listed sections have all been updated
to use inline rolls to cut down on chat spam but have been kept simple
to allow all users to use them.  Power users would likely customise them
to their own needs.

Added some colour (via CSS) to split off section from subsection
headings.

Some top half layout tweaks still needed but most of the ground work is
now done....bottom half of the sheet, including proficiency text areas,
weapon/armour lists, spell casting and equipment/treasure still need
reviewed