Fixes #1458 - Incorrect display of free mem on statistics page
lcd_outdezNAtt() on ARM was casting values to uint16_t.
Re #1458 - the cast is back, but cast to different type depending on platform. Gtest modernized.
Re #1458 - Forgoten files for new gtest
Re #1458 - added gtest for big numbers (>uint16_t)
Merge pull request #1460 from opentx/projectkk2glider/issue_1458

Fixes #1458 - Incorrect display of free mem on statistics page