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.
DBus-spec defines two different pattern matchings:
1) Path and namespace prefix matching. In this case, A matches B either
if both are equal, or if B is fully included in the namespace of A.
In other words, A has to be a prefix of B, but end with a separator
character (or the following character in B must be one).
This is used for path_namespace= and arg0namespace=
2) The other pattern matching is used for arg0path= which does a two-way
matching. That is, A must be a prefix of B, or B a prefix of A.
Furthermore, the prefix must end with a separator.
Fix the sd-bus helpers to reflect that. The 'simple_' and 'complex_'
prefixes don't make any sense now, but.. eh..
This patch removes includes that are not used. The removals were found with
include-what-you-use which checks if any of the symbols from a header is
in use.
