- make powermeter computation time based (again) to reduce config hassle and increase accuracy
- read at most one analog channel per MWii main loop cycle
- make faster analog reads an option with default off to increase accuracy
- fix vbat alarm level 1 (as pointed out in forum)
- detangle vbat & buzzer dependancy
- add OVERRIDE_PSENSORPIN option
- fix some left over errors from r1369 for 2 line displays



git-svn-id: http://multiwii.googlecode.com/svn/trunk/MultiWii_shared@1375 02679b44-d973-9852-f2fa-63770883b36c