stop ignoring validation errors

Sync fixes from a fork

found at https://github.com/akatrevorjay/edid-generator/issues/21#issuecomment-1025054600

Fix issue EDID bin length issue that apperead on recent versions of gcc
or objcopy (see gh-21). The fix has been originally suggested by
marwanramadan.

avoid hiding stderr from dos2unix to make it easier to notice problems

* 'master' of github.com:akatrevorjay/edid-generator:
  added -a paramter to local & removed debugging statements
  removed local -a from creating of variable lines. kept crashing under ubuntu 14.04
  failed because version of edid-decode had leading spaces in front of Checksum.  added pattern that matches leading spaces

leading spaces causing failed match in Makefile

failed because version of edid-decode had leading spaces in front of Checksum.  added pattern that matches leading spaces

* 'master' of github.com:akatrevorjay/edid-generator:
  Update README.md

Update README.md

Add dos2unix as a builddep, as compiling will otherwise fail with the error message "Makefile:32: recipe for target 'x.bin.ihex' failed".

Add in proper mode for thunderbolt monitor as it's checksum is off plus it's edid randomly decides when to respond
Also added in modes for Apple Thunderbolt Display and Retina MacbookPro.