Misc. bug fixes

**Bug (external):** Handle linebreaks (fixes #601).

Notes:
* Originally fixed by madskristensen/CssSorter#10
* Updated assembly.

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**Bug:** Filter rich-text in OLE (fixes #608).

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**Bug:** Overwrite after post-processing (fixes #599 & #612).

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**Bug:** Avoid duplicate inclusion in same execution (fixes #618). 

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**Feature:** Skip unobtrusive files generation during compilation (fixes #545).