Added day3 demo code for method_missing and defined_method
Added demo code upto method_missing
Merge branch 'day3' of github.com:budhrg/metaprogramming-course into day3
Updated ror demo for method_missing
Deleted ror demo
Added undef_method demo
Added method_missing warning and good practices
Added demo code for eval and its siblings, binding,
flat scope, blank slate etc
Updated demo code for define_method to define class methods
Updated demo code for flat_scop, binding demo, and define method