Revert "polishing the web application"

This reverts commit 95da0e3ac00011209068637a5b04a9c1a927a7e1.

Conflicts:
	Makefile
Clean identity-free version

Revert "normalisation of expressions"

This reverts commit fe861e117c15ae9df3c918f4cf3a57bbae7532f2.

Conflicts:
	exprtools.ml