installation: pip requirements

* Adds requirements files for Pythonic prerequisites, taken
  from the master branch, modulo some unnecessary dependencies.

  Useful for Python-2.6 based installations of maint-1.0/maint-1.1
  branches.  (Note that the maint-1.0/maint-1.1 branches shall
  remain Python-2.4 compatible.)

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>
Travis CI: initial release of configuration

Signed-off-by: Tibor Simko <tibor.simko@cern.ch>