Matitaweb:

1) Solves a bug in "Del hrefs"

2) Solves interaction glitches related to the disambiguation/error
reporting interface

3) Fixes the implementation of the Upload feature

4) Adds support for "low-users", who don't have permission to commit

5) Solves problems related to the multi-user mode

6) Limits direct file access to the html/ subdir of the Matita
installation (for security); all the files that must be accessed by a
web browser have been moved there

7) utf8macrotable.js uses numeric html entities instead of named
entities, to cope with incoherent behaviour of web browsers (named
entities being resolved to different unicode characters -- possible
bug in the web browser).

8) disables many debug prints