Added update.bat

Updates Red (stashes any changes) and its requirements

download_ffmpeg.bat

@@ -1,4 +1,5 @@
 @echo off
+pushd %~dp0
 IF "%PROCESSOR_ARCHITECTURE%"=="x86" (GOTO 32bit) else (GOTO 64bit)
 echo Couldn't detect system bitness.
 PAUSE

update.bat

@@ -0,0 +1,56 @@
+@echo off
+chcp 65001
+echo.
+pushd %~dp0
+
+net session >nul 2>&1
+if NOT %errorLevel% == 0 (
+    echo This script NEEDS to be run as administrator.
+    echo Right click on it ^-^> Run as administrator
+    echo.
+    PAUSE
+    GOTO end  
+)
+
+::Checking git and updating
+git.exe --version > NUL 2>&1
+IF %ERRORLEVEL% NEQ 0 GOTO gitmessage
+echo Updating Red...
+git stash
+git pull
+
+echo.
+echo Updating requirements...
+py.exe --version > NUL 2>&1
+%SYSTEMROOT%\py.exe -3.5 -m pip install --upgrade -r requirements.txt
+PAUSE
+GOTO end
+
+::Attempts to start py launcher by relying on PATH
+:attempt
+py.exe --version > NUL 2>&1
+IF %ERRORLEVEL% NEQ 0 GOTO lastattempt
+py.exe -3.5 -m pip install --upgrade -r requirements.txt
+PAUSE
+GOTO end
+
+::As a last resort, attempts to start whatever Python there is
+:lastattempt
+python.exe --version > NUL 2>&1
+IF %ERRORLEVEL% NEQ 0 GOTO message
+python.exe -m pip install --upgrade -r requirements.txt
+PAUSE
+GOTO end
+
+:pythonmessage
+echo Couldn't find a valid Python 3.5 installation. Python needs to be installed and available in the PATH environment variable.
+echo https://twentysix26.github.io/Red-Docs/red_install_windows/#software
+PAUSE
+GOTO end
+
+:gitmessage
+echo Git is either not installed or not in the PATH environment variable. Install it again and add it to PATH like shown in the picture
+echo https://twentysix26.github.io/Red-Docs/red_install_windows/#software
+PAUSE
+
+:end