Move types.c to types/

Reorganise in 3 subdirs:

types/
  Type management data structures (for both converter and reader lib)
converter/
  Trace converter (from format A to format B)
formats/
  Trace formats supported

Trace formats extend each type, specifying read and write functions for each
type.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>