various improvements to analysis.hole (#895)

* small fixes in analysis.hole

- updated for matoplotlib 1.5.1
- default to cmap viridis instead of jet
- small code refactoring

* replaced HOLE test trajectory

The old HOLE test trajectory XTC_HOLE was replaced with MULTIPDB_HOLE.
The old one contained repetitions of a static frame, the new one the dominant
mode from an elastic network model (generated by elNemo server). The new one
is a better example for future test cases and also to demonstrate the
function of the module --- see eg https://gist.github.com/orbeckst/64c0bd5a037b3e434cc8ee6732030252

* added raseed argument for analysis.hole.HOLE and HOLEtraj classes

- sets HOLE RASEED card to initialize the random number
  generator; this allows reproducible HOLE runs
- added tests for HOLE and HOLEtraj that use MULTIPDB_HOLE
  (and which *rely* on having RASEED --- otherwise each run
  gives different output)

Note that the test will not run on Travis because HOLE is not
available. We *could* install it, though:

   curl -L 'https://www.dropbox.com/s/jukpwlohhi20r17/hole2-NotForProfit-2.2.004-Linux-x86_64.tar.gz?dl=1' -o hole2-NotForProfit-2.2.004-Linux-x86_64.tar.gz
   cd ~
   tar xvf  hole2-NotForProfit-2.2.004-Linux-x86_64.tar.gz
   export PATH=${PATH}:${HOME}/hole2/exe

There is also a Mac OS X version:

   curl -L 'https://www.dropbox.com/s/5mzrsyp48i32je4/hole2-NotForProfit-2.2.004-Darwin-i386.tar.gz?dl=1' -o hole2-NotForProfit-2.2.004-Darwin-i386.tar.gz
   cd ~
   tar xvf hole2-NotForProfit-2.2.004-Darwin-i386.tar.gz
   export PATH=${PATH}:${HOME}/hole2/exe

* HOLE updates: work with axes and changed docstrings to NumPy style

- addressed @kain88-de's comment: plot() and plot3D() now properly
  honor existing axes
- converted all doc strings to NumPy
- added more docs and examples

package/CHANGELOG

@@ -14,7 +14,8 @@ The rules for this file:
 
 ------------------------------------------------------------------------------
 ??/??/16 kain88-de, fiona-naughton, richardjgowers, tyler.je.reddy, jdetle
-
+         orbeckst
+
   * 0.15.1
 
 Fixes
@@ -25,7 +26,8 @@ Fixes
     next (Issue #869)
   * Display of Deprecation warnings doesn't affect other modules anymore (Issue #754)
   * Changed nframes to n_frames in analysis modules for consistency (Issue #890)
-
+  * fixed incompatibility with newer matplotlib in analysis.hole
+
 Changes
   * Added protected variable _frame_index to to keep track of frame iteration
     number in AnalysisBase