First basic simple tests of a filter, as a tyep Filter and
method filter()
Tested powspec a bit
Now recoded from rastamat:
 - powspec
 - audspec
 - fft2barkmx
 - hz2bark
 - fft2melmx
 - hz2mel
 - mel2hz
 - postaud
 - dolpc
 - lpc2cep
 - spec2cep
 - lifter
 - mfcc (melfcc)
recoded from octave signal processing
 - hamming
 - hanning
 - specgram
 - levinson
 - toeplitz

Tested that mfcc.jl gives same answer for x=[1:1000] and HTK params...
 - removed varios println()s
 - added lifter
 - added 2-dim provessing
 - added feature warping
 - added shifted-delta-cepstra
 - added exports
 - added deltas()
 - attamt to modularize
 - removed types
 - add exception for N=0, because implementation is extremely slow
 - added multichannel support
Added Misc.jl, a module of misceleaneous features.
Renamed some oter files.
type Filter now in "filtertype.jl"
Merge branch 'master' of https://github.com/davidavdav/elftal

A merge from github