Debundle libsc from p4est package; introduce a new package libsc

This reflects current upstream development in debundling libsc from p4est.
Bump p4est to version 0.3.5

  * Debundle libsc from p4est
  * Fix build system so that autoreconf works without bundled sc
  * fix sonaming
Fix dependencies for sci-libs/dealii-8.(0|1).0, provide local use flag
Merge pull request #199 from tamiko/bump_p4est

Bump p4est; new ebuild for libsc
Add muparser and c++11 use flag to live ebuild
Merge pull request #200 from tamiko/minor_fixups_for_dealii

Minor fixups for dealii