encap: some templatization tweaks
docu: some docu on IMEXSweeper::predict
some code formatting tweaks

mainly reordered member functions according to order in base classes
exceptions must be thrown to be effective
Merge branch 'development' into release/v0.2.0

this is a backmerge of PR #65

* development:
  tests: further tweaking MPI advec test
  tests: mpi-fix for GTest
  tests: using another matcher
  tests: on MPI run do not execute GTest::run() on all ranks
  tests: stupid namespaces...
  tests: advec: using different matcher
  travis: enable APT caching and make tests more verbose
  travis: different repos for different versions
  travis: even more stupid...
  stupidity...
  travis: switch to other Boost PPA and test 1.53 and 1.55
sweeper: incorporate @memmett's remarks

see https://github.com/Parallel-in-Time/PFASST/pull/77#discussion-diff-16250875
Merge pull request #77 from torbjoernk/feature/sweeper-tweaks

LG
cmake: add option for GCC profiling

using `-ggdb3` and `-gp` with GCC enables verbose debugging and
profiling abilities useful for further analysis; also the tests will get
compiled with `-ftest-coverage` if both CMake variables
(`pfasst_BUILD_TESTS` and `pfasst_WITH_GCC_PROF`) are enabled and you
are compiling with GCC
cmake and tests: enable and provide test coverage analysis

Using lcov and genhtml and a little shell script we are now able to
generate test coverage results with a single command (assuming one has a
build available with GCC)