Make cpuload correct and more efficient for all configurations of NuttX

Currently cpuload assumes there are only 2 static threads - idle and init, this
is true only for "basic" config of NuttX, as there can be 3 more static threads:
paging, work0 and work1 - depending on config. In such cases cpuload
would mistake one of them for init (which in fact is always last), giving
incorrect results to "top"

Signed-off-by: Freddie Chopin <freddie.chopin@gmail.com>
Clean up and compact the output to fit inside a 80 column display.

Bug fix:
- running/sleeping count

Plus:
- added task state
- show the idle task (to make the number of tasks match the reported number)
- convert some calc to floating point where it doesn't hurt performance (for clarity)
- accept 'q' (standard) and escape to exit the program
mpu6000 driver support for setting rate
fixed attitude estimator params
gpio_led: PX4IO RELAY and ACC outputs support, some fixes
gpio_led: minor usage fix
Ammended UBlox driver to record SV Info, satelites_visible == satelites used. Info is recorded for all SVs, used or not. Might be useful for GPS debugging.
Merge branch 'master' into gps_fix
Some cleanup of NAV_SVINFO message handler
Merge pull request #324 from DrTon/gpio_led_io_relay

gpio_led: PX4IO RELAY and ACC outputs support
Merge branch 'master' of https://github.com/PX4/Firmware into gps_fix
Merge branch 'mpu6000_set_sample_rate' of https://github.com/fibr/Firmware into mpu_rate
Merge pull request #310 from PX4/att_fix

fixed attitude estimator params
Merged CPU load changes by freddie chopin
Merge branch 'master' of github.com:PX4/Firmware
Merge branch 'top' of https://github.com/a-ha/Firmware into top
Hotfix for GPS: Disable unknown message classes
Hotfix: Updated a MAVLink header
Hotfix for GPS driver
Minor additions to fix, pushing