support glob files in command line

[arthurzenika]

It would be nice to be able to use globs when calling speedometer.

For example in a directory I have : file1 file2 file3 otherfile1 otherfile2

I'd like to be able to do speedometer -f file* instead of speedometer file1 -f file2 -f file2

Added feature would be to split with -c according to the number of files to form a grid.