0.9.3 released

Change the requisite to Java 8
Fix the clone() method of the CodeBlock class
Fix the evaluation of functions which did not work when using arrays as arguments
Fix the ExpressionCombiner not taking correctly into account CodeBlock expressions
Add the "~" character to the list of allowed characters
Fix the behavior of the ExpressionCombiner used with a CodeBlock
Add the new "boolean" syntax for booleans in addition to "bool"
Fix the simplification of expressions with blocks, if-then-else, and while which were not handled
Change the package to org.expressionj
The distribution is now a Java 9 automatic module
Fix several exception messages
Allow to use a File or URL to parse an equation
Add a wiki