- MS561101BA baro: use float approximation instead of int64_t intermediate values
- MS561101BA baro: does not use 2nd order compensation under -15 deg
- MS561101BA baro: use 16 bit deadline timer instead of 32 bit

git-svn-id: http://multiwii.googlecode.com/svn/trunk/MultiWii_shared@1625 02679b44-d973-9852-f2fa-63770883b36c