Merge pull request #2 from favonia/master

Reference updater.
hits: suspensions
hits: cell complexes
move pushouts from chapter 7 to chapter 6
hits: style in the flattening lemma
Specified which characters are ok in labels
Replaced _ with - in labels
Increasing headheight to appease fancyhdr
Changed discussion about Excluded Middle, have no idea why the other changes in whitespace occurred
hits: the nontrivial self-homotopy of the identity map of the circle
Merge remote branch 'origin/master'
basics: fix universal properties comment
Better reference to UA -> not LEM
Added labels to unlabeled theorems
Restructured the chapter a bit, plan to finish later
A chapter on real numbers, just the outline
include the chapter on reals
Merge branch 'master' of github.com:HoTT/book
Added geometry.sty and ifxetex.sty.

The IAS machines and several other people seem to have old geometry
packages installed, that do not support \newgeometry and \restoregeometry.
We include our own geometry.sty, and also ifxetex.sty since the IAS machines
do not have it but geometry.sty depends on it.
working on preliminaries