vhdl codegen: AND, OR, NOT
Merge branch 'master' into vhdl-codegen-combinational

Conflicts:
	src/main/java/org/manifold/compiler/back/digital/DigitalBackend.java
checkstyle fixes
Merge pull request #149 from mtrberzi/vhdl-codegen-combinational

VHDL code generation: combinational logic
code review fixes
checkstyle fixes
Merge pull request #150 from mtrberzi/tuples

Tuple values
Merge branch 'master' into scopebuilding
checkstyle tho