v0.11.1

Overhaul the code structure to

• Simplify end user experience: everything goes through DynMathObject and MathWorld now
• Handle data
  • DynMathObject can hold a "column" of data, i.e. a 1D sequence of expressions
  • Expressions can be generic and use other objects from the MathWorld, instead of simple numbers.
• Be able to rename DynMathObject instances while still keeping their data
  • The main issue was to be able to rename a DynMathObject with an invalid name while still retaining the data.
    Until the user puts a correct name

Full Changelog: v0.10.1...v0.11.1