Move 'isntMostRecent' from Core to A in order that Core not have any
reference to the AUR specific PkgInfo.

'AURPkg' can hopefully be provided by packages from the ABS.
Just a little bit of tidying.
Move to using the Bash parsing lib for parsing PKGBUILDs.
Fix issue with PKGBUILDS using unusual characters.

Some PKGBUILDS had unusual characters and caused the search to fail.
Now they are read in forcing UTF-8 mode. Note that readFileEncoding
will still leak file handles (like readFile), which I don't like,
but this isn't any worse than the existing situation and it preserves
semantics. Potentially fix in the future by using strict bytestring
read and then unpack.