Removed kschur.py
trac #15622: Immutable graphs must not be relabeled
trac #15622: More informative exception message
Trac 15622: Review commit, fixing a misspelled doctest
Further improvements to splitting_field()
Do polynomial consistency check only for minimal dm
trac #15622: Rebase on 6.1.beta3
trac #15622: bugfix before #15623 gets merged
remove import kschur from classical.py and inaccessible if statements
Updated Sage version to 6.1.beta4
Trac #15575: Remove deprecated functions from symmetric functions

The class for each basis of the symmetric functions was deprecated from
the global name space in #5457 and the ticket was merged in sage-5.4.

The this ticket will remove the following functions:

 `kschur.py`

The way of accessing these functions since sage-5.4 is to get the basis
from within `SymmetricFunctions(R)`.

URL: http://trac.sagemath.org/15575
Reported by: zabrocki
Ticket author(s): Anne Schilling, Mike Zabrocki
Reviewer(s): Travis Scrimshaw
Trac #15622: Immutable graphs must not be relabeled

Now
{{{
sage: Graph(graphs.PetersenGraph(), immutable=True).relabel({})
...
ValueError: Thou shalt not relabel an immutable graph
}}}

Before, the following happened
{{{
sage: Graph(graphs.PetersenGraph(),
data_structure="static_sparse").relabel({})
...
AttributeError: 'StaticSparseBackend' object has no attribute
'vertex_ints'
}}}

This is actually another bug, as there should be a `vertex_ints`
variable in static sparse graphs. But that's another problem to be
addressed in another ticket `:-P`

Nathann

URL: http://trac.sagemath.org/15622
Reported by: ncohen
Ticket author(s): Nathann Cohen
Reviewer(s): Simon King
Trac #15626: Further improvements to splitting_field()

1. Implement an "early abort" option to stop if it's clear that the
degree will be huge.
1. Add some more examples (more indirect examples will be added by
#11905)

URL: http://trac.sagemath.org/15626
Reported by: jdemeyer
Ticket author(s): Jeroen Demeyer
Reviewer(s): John Cremona