Cleanup code

Dear Michael Meeks

This patch set are aimed to clean up the code of 'bootchart-collector' that is written in C language. In order to do that, I add log() & assert() functions that supports the DEBUG option. I also make both likely() and unlikely() macros for branch predict optimization. IMHO, this work would improve performance since gcc compiler speculates correctly whether the branch taken or not. As you already know, this technique is wildly used in Linux Kernel or Embedded system field.

Detailed items are as below.
- Bug fix: Remove misused unlink() function
- Move helper macros to macro.h file
- Clean up warning messages when compiling
- Add likely() and unlikely() macros
- Add detailed log() and assert() functions