Small fix to the objective eval in the N2 solver
Fixed the issue reported by @rienq related to general w. matrices...

... when using the N^2 solver.
typo in export_nlp_solver.cpp
Merge branch 'master' of github.com:mvukov/acado
removed warning from symmetricAD example
start of implementation of 'new' CN2 condensing
Merge branch 'master' of github.com:borishouska/acado
derivative member of unary operator
ignore txt files in basic_data_structures examples folder
optimization of unary operators in AD symbolics in terms of exporting expressions and their derivatives: much better reuse of auxiliary variables
solved bug regarding to recent AD improvements
fixed memory leak in unary_operator
unified the different ways of creating a tree_projection via operator=
unified the different ways of creating a tree_projection via operator= (2)
added mySubract feature to operator class
improvement of quotient operator in AD symbolics (not optimal yet)
simplified Product class
simplified Addition class
implemented a myPower feature
implemented a myLogarithm feature