Iftach Sadeh / ctools

This enables accessing the generated skymaps without calling 'save()' first

Removed 'runavgalpha' option, since computing the run-by-run significance is a non trivial thing and the difference in the residual counts map is negligible.
Added special handling in the significance computation when Non=0 to avoid NaN's.

…tskymap_RING_bkgsubtract

Added test to make sure ctskymap is able to run when RING background subtraction is requested.
Observation responses are now checked regardless of what type of background subtraction is requested.
Fixed origin for exceptions thrown in 'ctskymap::map_background_ring()'
Added log message to update user during run averaged alpha computation.

The outcome of the unit tests depends on the presence of the CTOOLS environment variable. If the CTOOLS environment variable is not present the unit test should fail, otherwise it sould succeed.

The ctobservation::first_unbinned_observation() and ctobservation::next_unbinned_observation() methods implement an unbinned CTA observation iterator. Using this iterator avoids code duplication and generates a uniform interface for tools to loop over CTA events lists.

Note that this breaks compatibility with Python < 2.6.

This command was run:
  autopep8 --select E101,W191 --in-place --recursive .

It fixes only these two issues:
  - W191 indentation contains tabs
  - E101 indentation contains mixed spaces and tabs

…)-function of individual ctools

The ctbkgcube tool generates a background model for cube-style analysis.

This sets up the system completly. From then on, unit test can be implemented.