bugfixes and (more) whitespace cleanup

[umlaeute]

• fixes a couple of serious bugs (#4, #5)
• a couple of type problems (use of t_int instead of int; use of short in callbacks where int is expected...)
• a couple of minor bugs introduced by typos
• a lot of compiler warnings (but not all ;-))
• printf-formatstring errors (trying to print long int with %d)
• drop some old and unsed files (fftease_setup.c; fftease_oldskool.h)
• and most importantly: (more) consistent use of whitespace
  • no tabs
  • 2-space indentation
  • no trailing whitespace