add symbol tracking to schematic for nodes, connections, constraints
Merge branch 'master' into symboltable

Conflicts:
	src/main/java/org/whdl/intermediate/Schematic.java
Update README.md
Update README.md
Restored coveralls support
refactor MultipleAssignmentException
Merge pull request #102 from mtrberzi/symboltable

Implement symbol table
Merge pull request #103 from manifold-lang/coveralls-69

Restored coveralls support