Corrected the calculation of the
Jordan decomposition. The 2-signature was broken
producing wrong genus symbols and wrong characteristic invariants
for certain FQMs.

For instance this happened:
sage: M = FiniteQuadraticModule('2^-2.2_1^1'); M
Finite quadratic module in 3 generators:
 gens: e0, e1, e2
 form: 1/2*x0^2 + 1/2*x0*x1 + 1/2*x1^2 + 1/4*x2^2
sage: M.jordan_decomposition().genus_symbol()
2_5^-3

But this is clearly wrong and at least inconsistent, as this example shows:
sage: M
Finite quadratic module in 3 generators:
 gens: e0, e1, e2
 form: 1/4*x0^2 + 1/4*x1^2 + 3/4*x2^2

Thus, the module 2_5^-3 is isotropic, whereas
2^-2.2_1^1 is in fact equal to 2_1^-3 and is anisotropic!

With this commit, I also implemented the p-signatures.
Added doctest for the latest change.

Also removed a lot of blank lines in the existing doctests
which caused them to fail.

A lot of the existing doctests still fail and need to be checked carefully.
Merge branch 'master' of github.com:fredstro/psage
Merge branch 'master' of https://github.com/sehlen/psage into stephan_fix
Added a new testing routine