added new files(img{vc,sa}.c for use as general utilities and api examples
made small changes to incomplete Makefile
added img{vc,sa}.c to .gitignore
made mnor fixes, and quite a few changes(function parameter order, debug logs, ...)
added helper functions(logging, string manipulation, malloc, ...)
made makefile to be able to compile img{sa,vc} exclusively
tried to make sys_warn() accept one argument, still no luck
started implementing --list option of imgvc