Separating Sources: kernel/spectrum
Separating Headers: kernel/spectrum
small update header
last header update
add: modular.lib
(cherry picked from commit 4033c6b71b5bdc43798b4183c90512f5d4871308)

Signed-off-by: Andreas Steenpass <steenpass@mathematik.uni-kl.de>

Conflicts:
	Singular/singular-libs
Merge pull request #555 from steenpass/modular_sw

add: modular.lib
Merge pull request #550 from adipopescu/Spectrum

Separation of SPECTRUM-related code inside `kernel/`
add: Tst/Short/modular_s.tst to ok_s.lst
Separating Sources kernel/linear_algebra
Separating Headers: kernel/linear_algebra
removed: unused references to gmp_output_digits
comments by Claus Fieker (CF)
removed char_flag from coeffs
fix: definition of nlInit2gmp
fix: tr.590
fix: tr.588  reconsidered (syz,intersect,modulo and returnSB)
tests for dumb things: tr.590,588,579,576
Merge pull request #551 from adipopescu/LinearAlg

Separation of LinearAlgebra-related code inside Kernel
Separating Sources kernel/maps
Separating Headers kernel/maps