Tags: andrei91ro/pep

chmod executable and added Usage message

Added the negation operator ~ that allows to specify negative values

Added .csv file output of all variables and enzymes at each simulatio…

…n step

Fixed enzymatic bugs:

    1) Fixed enzymatic programs execution bug (distribution phase)
    2) Fixed variable/enzyme reset bug
        Pobject.(isPartofProductionFunction replaced with wasConsumed)
        both name and meaning

Added generic functions sqrt, abs, log, log10, log2

Added common trigonometric functions:

    sin, sind, asin, asind
    cos, cosd, acos, acosd
    tan, tand, atan, atand, atan2, atan2d
    cot, cotd, acot, acotd

added support for binary boolean operators (< <= > >= == !=)

Added support for negative list values (var0, e0, ...)

working corectly in Python 2.7.12

Added support for P systems with enzymes