Merge pull request #10 from arition/develop

Develop
[Ref]: Get rid of XML parsing
[Add]: Cache the track info
Port to Python3 by 2to3
[Add]: Wait between downloading songs
[Mod]: default remove timetags in lyric
[Mod]: get the cover in highest resolution
Merge branch 'pr/3' into python3-port

Conflicts:
	xiami.py
[Fix]: Bug Fixs
Port xiami_dl.py to Python3
Port xiami_util.py to Python3
[Fix]: More Bug Fixs
[Doc]: Update README