Merge pull request #49 from neavo/master

update v0.1.8.1 to maven
DrawTask: Simplify the RectCache
AndroidDisplayer: calc the multline-itext-textHeight effective
DanmakuTextureView: fps()
DanmakusIterator: optimize allocations
DrawTask: refresh fullscreen
DrawHandler: update in the new Thread when availableProcessors>3
DrawHandler: fix hide/show issue
DrawHandler: lazy refreshing
DrawTask: lazy subset
DanmakuRenderer && DrawTask: report more rendering-state from renderer to darwtask
Danmakus: add a ST_BY_LIST type
CacheManagingDrawTask: increase the slopPixel for findReuseableCache
DrawHandler: block refreshing after hideDanmaku
DrawTask: optimize the managing of live-danmakus
Update README.md
IDanmakuView: add getCurrentTime() for getting the accurate play-time. use this method intead of parser.getTimer().currMillisecond
fix renderingState issues && fix typo
IRenderer && DanmakuRenderer: remove geRefreshArea()
Fix priority of HandlerThread