Added files for starting the joli
(jacobi forms of lattice index) implementation
Added sz_trace_formula.py (a copy of the old sz_trace_formula.sage),
which still has to be py-ed
Revised (py-ed) sz_trace_formula.py so that it works as part of psage
Added traces.py (a copy of dimension_jac_forms.sage),
which, however, is not yet py-ed
py-ed traces.py
We can now make the functions in the modules traces and sz_trace_formula accessible
in a session which uses 'from psage import *'
Added the package joli as subpackage to the package modform
Added a constructor function for instances of Lattice_class
py-ed various files
o an ennoying bug (?) in sage: kronecker(a,b) and a.kronecker(b) give
  back Integer and int, respectively.
Added more lattices and cured minor bugs
py-ed lattice.py
py-ed jacobi_form_module and debugged
Rewrote the algorithm for computing the Poincare polynomials
Fixed the "range Python vs. Sage" bug
o range(x) is all integers strictly less than floor(x)
  whereas the sage coercing system suggests that it should be
  all integers stricly less than x.
  Fix: if you want the last behavior, then call range (x.ceil(()).
Converted Lattice_class into a 'wrapper' around \code{ZZ^n}.
Changed enumerating vectors whose norm is below a certain bound
Revised the Jacobi forms a bit
Added twist() to lattices.py
Merge branch 'joli'

Conflicts:
	psage/modform/__init__.py