Merge pull request #1 from GkAntonius/master

Bug fix
Merge pull request #2 from GkAntonius/master

tests created for htc
 Doc cleanup
 Add new subpackage for wxPython GUI widgets
 All *_File objects now derive from the abstract class AbinitNcFile.
 More GUI tools.
 New version of PopupMenu based on inheritance.
 Oops, changes were not committed
 Continue to add WX Gui widgets.
 Add new object MDF_File to access the results of the BSE run.
 Add WX panel to analyze the WARNINGS/ERRORS/MESSAGES reported by abinit.
 Small App to navigate the AbinitEvents in a notebook.
 Add directory containing demos of the WxWidgets Apps.
 Trying to rationalize the treatment of the different files.
 Refactoring
 New version of PopupMenu that includes callbacks for text files (.log, .out)
 Replace FloatSpin with SpinCtrlDouble
 Add frame to plot the results reported in the TIMER section (abinit output file).
 New wx frame to facilate results comparison.
 More stuff related to WXwidgets.