PX4-NuttX/nuttx branch test: px4-master_auto_rebase

NuttX:
 - https://github.com/PX4-NuttX/nuttx/tree/px4-master_auto_rebase
 - PX4/NuttX@a71b83a

Changes from PX4-NuttX/nuttx (PX4/NuttX@d5c12b2) in current PX4/master (ceae2f8)
PX4/NuttX@d5c12b2...a71b83a

a71b83a (HEAD, origin/px4-master_auto_rebase) [PX4: WIP] Fix transmission status handling in the serial interrupt
6c6f767 [PX4: REJECTED] cstdint fix
30e40a3 [PX4: REJECTED] add math.h
53887ac [PX4: WIP] Jenkinsfile
07b1326 (origin/master) configs/stm32f4discovery/src/stm32_rgbled.c:  Krassimir Cheshmedzhiev claims that sys/types.h needs to be included to avoid undeclared 'OK'
cca8771 include/nuttx/sensors/bh1750fvi.h: Eliminate a warning.
3f5a3d0 tools/gencromfs.c:  Need to include stdint.h.
b0178e9 toosl/cfgdefine.c:  Add more configuration variable names that need to be de-quoted.
49d6f44 drivers/usbhost/usbhost_max3421e.c:  Select full duplex mode as the first step of the initialization.
a74246d Squashed commit of the following:

Apps:
 - https://github.com/PX4-NuttX/apps/tree/px4-master_auto_rebase
 - PX4/NuttX-apps@517239f

Changes from PX4-NuttX/apps (PX4/NuttX-apps@36806ba) in current PX4/master (ceae2f8)
PX4/NuttX-apps@36806ba...517239f

517239f (HEAD -> px4-master_auto_rebase, origin/px4-master_auto_rebase) [REJECTED] add-var-expansion-in-nsh-parse.patch
aea8d94 (origin/master) apps/examples/nsh:  The symbol table name and size variale names can now be configured.
5ecec24 There many occurences of the global variable g_exports and the opportunity for collisions.  Make the global variable names unique.
e778a69 Correct more improper global variable naming:  All must begin with g_
7c1082b apps/examples/nsh:  Clean up some rather complex conditional compilation associated with the previous commit.
0ea260e apps/examples/nsh:  Add logic to automatically register an application symbol table as part of NSH initialization.
6b93881 Merged in masayuki2009/nuttx.apps/fix_helloxx (pull request #144)
654ee7e apps/examples/elf, module, posix_spawn:  Correct naming of global variables that violations the naming requirements of the coding standard.
db9c56e apps/examples/powerled:  Eliminate a warning about an uninitialized variable.
e66470d Merged in raiden00/apps (pull request #143)