first draft of IntegerLattice class
modern interface to fpLLL
documentation changes
actually use fpLLL in IntegerLattice.shortest_vector
added more of a class hierarchy
lattices inherit from Parent, IntegerLattice is a Facade for ZZ^n
added HKZ reduction
added lattices to reference manual and fixed pdf building errors
Merge branch 'u/malb/15976_integer_lattice' of git://trac.sagemath.org/sage into ila
jacobi method documented (and now without cruft from other branch)
Lattice -> RealLattice
fixed copyright notice
removed sage.lattices and mode sage.lattices.integer_lattice to sage.modules.free_module_integer
fixed documentation
guard shortest vector computation with sig_on/sig_off
Merge branch 'develop' of trac.sagemath.org:sage into integer_lattices
Merge branch 'develop' of trac.sagemath.org:sage into integer_lattices

Conflicts:
	src/doc/common/conf.py
fixed incomplete merge
corrected whitespaces; rewrote long lines
corrected whitespace errors, rewrote long lines (in fplll.pxi)