TPAC: href not valid on 'button' tags

The 'Clear Form' button was moved to a button tag, which solved a
display issue but didn't actually clear the form.  Let's make it
an <a> again.

Signed-off-by: Dan Wells <dbw2@calvin.edu>
Signed-off-by: Ben Shum <bshum@biblio.org>
TPAC: Consolidate and simplify button styles

TPAC has at least two distinct types of buttons, those created by
input tags, and those created by anchor (that is, <a>) tags.  This
commit simplifies and consolidates the styles used for both types
of buttons.

At least in Firefox, inline blocks display in a closer size rendering
to <input> tags than plain 'display:inline'.  The switch doesn't seem
to hurt in most cases in IE, FF, or Chrome, so let's do it.

Two cases where inline works better are the floating 'My Account' and
'dash' buttons'.  They already have special classes, so let's revert
those back to inline.  In fact, let's make the logged-in 'dash'
buttons share the style of the 'My Account' button which got us there,
and make all three buttons more visible when hovering.

Inputs do not inherit the body font by default, so let's apply it for
better display consistency.

Finally, Firefox inputs have some extra space around them; let's make
a modest attempt to remove that.

Signed-off-by: Dan Wells <dbw2@calvin.edu>
Signed-off-by: Ben Shum <bshum@biblio.org>