DVB EPG: Some strings weren't correctly displayed in some cases.

Null-terminated strings weren't correctly handled.
Cosmetic: fix typo "lenght" instead of "length".
Cosmetics: build.bat and gccbuild.bat error handling improvements.
Use /Silent switch for gccbuild.bat when building through MSVC to avoid unneeded pause message
Add /Nocolors switch to disable colors in batch files output.
Disable colors also for /Silent switch.