main.lua: Replace tabs with spaces and fix identation on main().
main.lua: Add command-line argument for snabbswitch to support '-jv'

 * This causes luajit to shows verbose information about the progress
   of the JIT compiler. It logs the information to 'file'.

 * You can use "/dev/stderr", "/dev/stdout" or "-" as file names if
   you want the information to be printed on the screen.
Merge pull request #294 from clopez/support-jv

Add command line argument to support printing verbose information about the JIT compiler (-jv)