Also some general minor sanitizer improvements.

    - DriverFramework in PX4/Firmware (1ce7e8d89a16262afe07d7487e55a2ec05985627): https://github.com/PX4/DriverFramework/commit/721ace3e797f141f0950144bace6a30f6aa1325a
    - DriverFramework current upstream: https://github.com/PX4/DriverFramework/commit/9f456acb3c8d70df3cd8906123388935dd6303f6
    - Changes: https://github.com/PX4/DriverFramework/compare/721ace3e797f141f0950144bace6a30f6aa1325a...9f456acb3c8d70df3cd8906123388935dd6303f6

    9f456ac 2018-09-30 Bart Slinger - Increase DriverFramework priority to SCHED_PRIORITY_MAX

 - fixes #10599

A filtered update update interval is calculated for each receiver.
If dissimilar interval data is detected, blending occurs when data is received from the slower of the receivers.
If similar interval data is detected, blending occurs when receiver data with similar time stamps is available.
If no data is received from either receiver for longer than 300msec, then no blending will be performed and the most recent data will be used instead.

- previously it was possible to get a Position Control rejected message
  without further advice what was actually wrong. So now we report warnings
  even if gps is not required for arming (which could be annoying too...).
- the GPS failure message was very generic, making it hard to debug the
  cause. Now we check every bit and send an appropriate warning

All strings were checked not to exceed the maximum length of 50 characters.

estimator status init is not required.

So that they can be used for reporting errors.

1 was too high to pass the EKF2 test (EKF2_REQ_SACC which is 0.5 by default)
and thus switching into position mode in HIL was not possible.

 - revert once #10590 is resolved properly

module list is now the same as posix_ocpoc_ubuntu.cmake

There were cases where the console was continuously spammed with activation
failure messages.

   This extends the  Capture support for FMU
   CHAN 5 and 6.

'source' is not POSIX

This uses the systems default shell:
- Ubuntu: dash
- Fedora: bash

Since bash is invoked via /bin/sh, it operates in POSIX mode:
  https://tiswww.case.edu/php/chet/bash/POSIX

- remove '# Ignore the expand_aliases command in zshell.'
  Not needed because the shell operates in POSIX mode
- [[ is bashism -> use [
- autostart_files=( $autostart_file_match )
  is not supported in dash, so use 'ls'
- shellcheck runs the dash flavor, since dash is a minimalistic shell.

Tested on dash & bash.

- NuttX supports both versions
- POSIX shell only supports '='

For consistency & documentation