Change definition of (i)fft, add more properties in the discrete case, improve some minor notational issues.

- Change domain of fft(f)(omega) from omega in [N_1] x ... x [N_n] to omega in [N_1]/N_1 x ... x [N_n]/N_n
- Add discrete translation and matrix multiply property
- Change transpose to hermitian transpose in continuous and discrete ft
- Change color in support diagramm from red to blue
Implement ridgelet transform