www: Do not use a small fonts for the core text

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@197793 91177308-0d34-0410-b5e6-96231b3b80d8
www: Do not use a fixed with, but use max-width

Further:

  o ensure that the header is properly readable even on smaller screen sizes.
  o Shorten the table of contents of the documentation section.

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@197794 91177308-0d34-0410-b5e6-96231b3b80d8
www: Fix typos

Reported-by: Dmitry N. Mikushin <maemarcus@gmail.com>

git-svn-id: https://llvm.org/svn/llvm-project/polly/trunk@197796 91177308-0d34-0410-b5e6-96231b3b80d8