tidy up standalone generation pipeline

[increpare]

I found out that part of the standalone generation process (#780) was adding spaces to the ends of lines, so try to move to a better process (and maybe try better optimising/minifying standalone_inlined.txt file to make it smaller

[increpare]

together with 8645061 and 8cbffb0, this task is done.

Standalone file export size of example project reduced from 368kb->212kb .