Battery Life eXtender (BLX)

This is a simple port of Ezekeel's BLX mod to the Nexus 4.

See this thread for more information: http://forum.xda-developers.com/showthread.php?t=1257497

Let's keep the same sysfs implementation so that apps, such as Trickster MOD, can support this.
BLX: Set default limit to 98
halfbreed calibration

Change-Id: I699ca28b428bbb4e5ccf5f0adcf35f2f99b240d3