LayoutEngine Implementation

[Brixbiru]

Added the math to calculate X and Y coordinates

[AnishBramha]

Changes in this branch:

• Transpiler and layouting engines added as their respective directories transpiler/ and layout/
• Test files updated to be compatible with provided grammar:
  • c2.stb: Removed negative values (not recognised by grammar)
  • c4.stb: Restructured transitions to not cause forward definition/redefinition issues (originally incorrectly placed for parser testing purposes)
  • c7.stb & c10.stb: Incorrect events/triggers renamed
• Added TestTikz.java, to compile testcase files for the new engine
• Directory tikz_outputs contains output LaTeX code, with a script runall.sh to run a local XeLaTeX compiler on all files
• Makefile updated to compile the new transpiler and layouting engine directories