When the constructor for the cos/sin table was changed from
number of bits to number of points all usages thoughout the
code should of been changed, but this was missed in RDFT and DCT.
Fixes Trac#10683.
Makes the DCT code use constants of type float in expressions which only use
type float values otherwise. This silences some floating point conversion
warnings in the DCT code.
This removes the large static tables from the binary (which saves 500K
to 1Mb of binary size) and replaced them with a class which generates
the required tables as needed in RAM. This has been tested with QDM2
and shows no obvious performance degredation and Memprof shows no
significant rise in RAM usage.
