UML diagram + gitignore

Made a (very simple) UML diagram of the system.
Made a gitignore file.
Translatorr + JUnit

Added the translator interface.
Added JUnit yo build path.
UnsupportedExpressionException + Latex2Matlab

Added the UnsupportedExpressionException.
Added a test list text file.
Added Latex2Matlab class and began TDD implementation.