Add type checking in __setitem__ on strategy profiles.

Raising an exception if an invalid indexing object passing to
__setitem__ operator.
Merge remote-tracking branch 'hokein/fix_issue58' into integrate
Bugfix: setting probability on a rational mixed strategy profile was raising an exception.
Improve efficiency of path-following for QRE tracing.

Improves the efficiency of the Python implementation of path-following,
used in computing QRE.  Primarily, this is done by taking greater
advantage of numpy to handle linear algebra rather than looping.
Speedups over the previous implementation are substantial.  Testing
has been done (primarily on some all-pay auction examples) to confirm
that the old and new implementations return the same results.
Implement explicit copy operation for strategy profiles.
Hide canonicalization and cached values as implementation detail.

The extensive game representation generates derived values (notably
sets of reduced strategic form strategies), and relies internally on
a numbering of elements of the game (nodes, information sets).

This has previously been imperfectly encapsulated -- historically,
ultimately, for "performance" reasons.  Aside from being questionable
practice, performance is unlikely to be an issue; processors are
much faster now, and the time spent running computations on a game
dominates any time spent building the game.

This changeset hides these implementation details.  This simplifies
the use of the classes externally (and fixes a bug in the Python
interface related to using games which had not been canonicalized).
However, a more complete solution would involve a more sophisticated
implementation which did not require objects to be renumbered in
a canonical way.
Implement access to beliefs in Python for behavior strategy profiles.
Nomencalture in behavior strategy profile properties.

  *Rename in C++ part:
     1. GetInfosetProb -> GetRealizProb
     2. GetNodeValue, GetInfosetValue, GetActionValue -> GetPayoff
  *Rename in Python part:
     1. Expose realiz_prob interface.
     2. action_value -> payoff

GetRealizProb function computes the probability of reaching a node and
an information set.
GetPayoff functon computes the expected payoff conditional on reaching
a node, an information set and an action.
Standardize nomenclature for payoffs and probabilities in strategy profiles.

This commit standardizes naming conventions for functions computing
payoffs and probabilities on pure and mixed profiles.

All functions which return payoffs or conditional payoffs are now named
GetPayoff() in C++ and payoff() in Python.  This includes functions
formerly known as GetActionValue(), GetStrategyValue(), GetInfosetValue(),
GetNodeValue().

All functions which return probabilities of events occurring are now
named GetRealizProb() in C++ and realiz_prob() in Python.  This affects
the function formerly known as GetInfosetProb().
Implement wxWidgets 2.9.4 compatibility in graphical interface.

This revises the graphical interface implementation to support
wxWidgets 2.9.4.

wxWidgets 2.8.12 compatibility is retained.  Notably, this requires
that dcsvg.(cc,h) remain; this is available in wxWidgets 2.9.4
but not in 2.8.12.  The 2.9.4 build uses the wxWidgets implementation.

There is a bug involving drag-and-drop on OS X with wxWidgets 2.9.4
This requires using 2.8.12 for OS X builds, which requires some
extra steps when building on Snow Leopard.  These are now documented
in the manual.
Fix the build error with wxWidgets 2.8.12.
Rename configure.in to configure.ac to match preferred autotools style.
Deal with absence of lxml module gracefully in reading/writing GTE file format.
In square matrices, implement more explicitly the absolute value of a double.
Merge branch 'master' into symlp