There are more than enough calls doing string manipulations to deserve
its own files, hence do something about it.
This patch also sorts the #include blocks of all files that needed to be
updated, according to the sorting suggestions from CODING_STYLE. Since
pretty much every file needs our string manipulation functions this
effectively means that most files have sorted #include blocks now.
Also touches a few unrelated include files.
Probably a typo, checking 'ret' instead of the return value 'p'. This
might cause the function to return failure, even though it succeeded.
Furthermore, it might leak resources.
