Use '-k1M' with aria2

[cnbeining]

For small files(0.01~20M), since the default minimum piece site of aria2 is 20M, aria2 would use only 1 thread when downloading, which makes the speed restricted.

I would recommend that a '-k 1M' being added to the arguments to enhance the performance in such circumstances.

[acgotaku]

OK Updated. Please update to 0.1.5 version.