Main point: add the ability to have lmg on read-only media and do the ca...

Main point: add the ability to have lmg on read-only media and do the capture on another media which is read-write to preserve integrity of your toolset

Other minor changes:
- exit if script is executed as non-root; 
- warning if a mount point is flagged as showexec which means vfat (in this case, can't execute directly dwarfdump and shell script); add another option for caseid (internal identification); 
- looking for tools in directory one level ahead to avoid mixing downloaded files; 
- on my test box (lubuntu 14.04), lime was generated without CPU suffix so handling that 
- except caseid part, tested (one box)