Fix battery status reading, add "fully charged"

Commit 438c501fae2486f1520eb485c14662c3a632fd2c introduced support for HID++ 1.0
battery information. That accidentally selected the third parameter instead of
the second one. This commit fixes that and additionally adds a "fully charged"
status too that was found on the K800.
Merge pull request #26 from Lekensteyn/hid10-battery

Fix battery status reading, add "fully charged"