Doc: new Compiler options in Build & Run options

Describe the new platform codegen and linker flags options
and the custom parser settings.

Update and add screenshots.

Change-Id: I64498258930ce1f912bcd8891a6b55f40d903f2c
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@digia.com>
Reviewed-by: André Hartmann <aha_1980@gmx.de>
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@digia.com>