Better errors: unhandled error cases, host API errors

[morew4rd]

• lyte.load_image non-existing path
• Shader compilation failures
• lyte.is_key_pressed/is_key_down/etc with invalid value crashes
• Syntax errors

Need to catch these and display them in the window instead of closing the window. Reporting on the console is a workaround but not all folks care about or want to use console.

Handled

• lua assert failures

(I'll keep updating this list as I test/hit issues.)

[Zorbn]

lyte.is_key_pressed/is_key_down/etc with invalid values also has this issue (ie: lyte.is_key_pressed("!") crashes)

[morew4rd]

Syntax errors in code can show up like this:

In a sense there are handled that they're shown in the UI. But error message is not clear.