chg: update tasks.lib

Improve handling of internal data structures, especially intvecs.
(cherry picked from commit 091fbfe87825a276fac0079c772304a96a7cb118)

Signed-off-by: Andreas Steenpass <steenpass@mathematik.uni-kl.de>
Merge pull request #483 from steenpass/tasks_sw

chg: update tasks.lib
fix: conversion to libfac in char series and neworder
chg: added test for ticket 549
Merge pull request #485 from mmklee/conversion

Conversion
chg: added new conversion for polys over Fq (requires FLINT at least 2.4)

Conflicts:

	factory/FLINTconvert.cc
chg: use for univariate factorization over Fq
chg: use FLINT instead of NTL in squarefree factorization
chg: first part of changes in facMul
chg: second part of changes to facMul.cc
chg: use FLINT to factorize polys over Fq in facFqBivar
chg: fixes to stay backward compatible
bug fix due to unset NTL characteristic
fix: converting the wrong poly to FLINT
chg: more concise functions for Kronecker substitution and reversion of the very same
fix: bug in computing bounds for factor recombination
fix: compiler warning in case FLINT >= 2.4 is around
chg: new function to get coeffs over extension with FLINT
chg: replace NTL by FLINT in bivariate factorization over FF in case a field extension is needed
chg: deleted unused tryCRA and tryExtgcd