Remove MayAliasSet class

The MayAliasSet class is currently not used and just confuses people. We can
reintroduce it in case need a more precise tracking of alias sets.

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@201191 91177308-0d34-0410-b5e6-96231b3b80d8
Add link to polyhedral.info

This website provides general information about polyhedral compilation.

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@201192 91177308-0d34-0410-b5e6-96231b3b80d8