Bump revision to 2019

Bump revision to 2018

Update nspire-io

Bump revision to 2016

Use same repeat count in the 5.2.0 installer as used for 4.5.3

Appears to be more reliable

Bump version to 4.5

Remove leading whitespace in README.md

Merge pull request #25 from Legimet/makefile-check-submodules

Check for submodules in makefile

Use ndless_resources.tns in installer-3.6 as well

Add sdl-config script to make porting easier

-Requires setting the path to sdl-config like ./configure --width-sdl-exec-path=`nspire-tools path`