Fixed make/firmware-defs.mk to use PYTHON env variable

It caused build errors on systems where python points to python3.

Signed-off-by: Francesco Nero <nerofrancesco@hotmail.com>
python uavtalk: fix usage of 0 (NULL) rather than "None"
python logview: remove debug code
Removed tools entries that are duplicated in tools.mk
Added missing Windows path export
Fixed error message on non-Windows environments
Add button, change save to file button name
Merge pull request #1140 from larsjohnsen/fix_make_preserve_error

Fixed make error on non-Windows environments
Merge pull request #1141 from metropt/add_clearLog_button

Add button to clear log
GCS:Telemetry Schedular, create a fill with value dialog
Removed redefinition of PYTHON var in makefiles

Also fixed some typos in some makefiles.

Signed-off-by: Francesco Nero <nerofrancesco@hotmail.com>
Merge pull request #1132 from solidgoldbomb/python-uavtalk-fixes

Python uavtalk fixes
releases: add script to assign short labels to downloadable assets
Merge pull request #1145 from solidgoldbomb/release-asset-info

releases: add script to assign short labels to downloadable assets
GCS:Telemetry schedular add space after comma
GCS coreplugin:avoid loading each configuration twice on startup
GCS systemhealth:Only display missing elements warning once
GCS:Telemetry scheduler -prevent user from inputing invalid values.
Merge pull request #1143 from guilhermito/schedular_helper

GCS Telemetry Scheduler: create a fill with value dialog
Merge pull request #1139 from jan76/tools1

Removed tools entries that are duplicated in tools.mk