Changes proposed by Mathieu Malaterre from the GDCM project... Thanks a lot Mathieu

Changes proposed by Mathieu Malaterre from the GDCM project... Thanks a lot Mathieu
- '//' replaced by '/* */'
- inclusion of int.h in int.c
- inclusion of j2k.h in int.h in order to export symbols
- adding (void) var when a variable is declared but not used
- some explicit cast
- CLOCKS_PER_SEC is declared as float in bcc55, so there is a need to cast it to int for the modulo operation
- some variables changed from float -> double